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Low-Carb Balsamic and Onion Pot Roast (How to Make Pot Roast in a Slow Cooker)

This Low-Carb Balsamic and Onion Pot Roast is a delicious and healthy dinner that’s made in the Crockpot, and this post also has tips for How to Make Pot Roast in a Slow Cooker. And this low-carb dinner is also gluten-free, Paleo, Whole 30, and South Beach Diet friendly. Use Slow Cooker Recipes to find more recipes like this one.

Click here to PIN Low-Carb Balsamic and Onion Pot Roast!

Low-Carb Balsamic and Onion Pot Roast found on KalynsKitchen.com

When my friend Bonnie told me she had made this Low-Carb Balsamic and Onion Pot Roast and liked it, I immediately realized I wanted to make it again just so I could take better photos! Bonnie was kind enough to say that she didn’t think the old photos were that bad, but trust me, these updated photos give you a much better idea of what a tasty recipe this is! This pot roast is just the thing to cook on low all day in the slow cooker while you’re at work, and dinner will be ready when you get home.

How to Make Pot Roast in the Slow Cooker:

I’m not a pot roast expert, but I’ve made pot roast in the Crockpot enough times to have strong opinions about how it should be done. There are three things I think are important to remember.

  1. First, Brown the meat well before you put it in the Crockpot because browning creates flavor.
  2. Second, don’t use too much liquid for any crockpot cooking, but especially for pot roast.
  3. Third, be sure there is plenty of flavor in the liquids you’re using. All day cooking can make foods bland if there isn’t a flavorful liquid.

I’m using all those tricks in this pot roast recipe. If there are others reading this who use a slow cooker to make pot roast, chime in with some comments about good tips for making pot roast in the Crockpot.

How to Make Pot Roast in a Crockpot and Low-Carb Balsamic and Onion Pot Roast found on KalynsKitchen.com

I used a very thick chuck roast from Costco; here’s how my roast looked after I trimmed it. (I had to cut it in half to get it to fit in my Crockpot.) I save all the scraps in a container which goes in the freezer, and then use them to make beef stock. Rub meat on both sides with steak seasoning and black pepper, then brown the roast well. In a small saucepan, reduce 1 cup beef stock to 1/2 cup. While the meat browns, cut the onions and put them in the Crockpot. When the meat is brown put it in slow cooker on top of the onions, then deglaze the pan with 1/4 cup water, scraping off all browned bits, and add to reduced beef stock.

How to Make Pot Roast in a Crockpot and Low-Carb Balsamic and Onion Pot Roast found on KalynsKitchen.com

Add balsamic vinegar and tomato sauce to beef stock and pour over pot roast. Cook on low 6-8 hours, until meat is tender. I drained all the liquid from the Crockpot and used a fat separator to remove the fat. (This is too much liquid; I reduced the amount in the recipe I’m giving you.) After the fat is removed, reduce the liquid by about 1/3 to make a sauce. You could thicken it, but I didn’t think it needed it. You might think they’d be too done from being in the Crockpot all that time, but the onions were delicious as well as the meat.

Make it a Low-Carb Meal:

This would taste great with Pureed Cauliflower with Garlic, Parmesan, and Goat Cheese for a low-carb meal.

More Tasty Beef Recipes for the Slow Cooker or Instant Pot:

Instant Pot Barbacoa Beef ~ Taste and Tell
Low-Carb Stuffed Peppers with Beef, Sausage, and Cabbage ~ Kalyn’s Kitchen
Slow Cooker Beef and Broccoli ~ Well Plated
Crockpot Recipe for Southwestern Pot Roast ~ Kalyn’s Kitchen
Instant Pot Beef Short Ribs ~ That Skinny Chick Can Bake
Green Chile Shredded Beef Cabbage Bowl (Slow Cooker or Pressure Cooker) ~ Kalyn’s Kitchen
Slow Cooker or Instant Pot Beef Recipes Index ~ Slow Cooker or Pressure Cooker

Weekend Food Prep:

This recipe has been added to a new category called Weekend Food Prep  to help you find recipes you can prep or cook on the weekend and eat during the week!

Balsamic and Onion Pot Roast in the Crockpot

This Low-Carb Balsamic and Onion Pot Roast is a deliciously healthy dinner that’s made in the Crockpot.


  • 3-4 pound boneless chuck roast
  • 1-2 T steak rub (see notes)
  • black pepper to taste
  • 1-2 T olive oil (depends on your pan)
  • 1/4 cup water to deglaze pan
  • 2-3 large onions, peeled and thickly sliced
  • 1 cup beef stock, reduced to 1/2 cup (can use a can of beef broth, but be sure to reduce it)
  • 1/2 cup balsamic vinegar (see notes)
  • 1/2 cup tomato sauce (You can substitute one can diced tomatoes, drained well. I might puree the tomatoes.)


  1. Trim as much fat as you can from roast, and cut if necessary to fit into Crockpot. Rub meat well with steak seasoning and black pepper.
  2. Heat heavy pan with small amount of olive oil and brown roast well on both sides. This will take a few minutes; don’t rush the browning step.
  3. While roast browns put 1 cup beef stock in saucepan, bring to a boil and cook until reduced to 1/2 cup, then let cool slightly and mix in balsamic vinegar and tomato sauce.
  4. Peel onions and cut into thick slices. Deglaze pan with 1/4 cup water and add to sauce mixture.
  5. (You can stop at this point and refrigerate browned roast, cut onions and mixed sauce ingredients and then put them in the Crockpot when you go to work in the morning. Don’t refrigerate them in the crockery liner. Having the meat start out cold will add several hours to the cooking time, which will be good if you’re cooking it all day while you’re away.)
  6. Place onions in bottom of Crockpot. Put meat on top of onions and pour beef stock mixture over.
  7. Set Crockpot to low and cook 6-8 hours, until beef is tender. The meat might be partly submerged in liquid after this much time. (If I am home, I might turn the meat once or twice.)
  8. Remove meat from crockpot and cover with foil to keep warm.
  9. Drain liquid from Crockpot and remove as much of the fat as you can with fat separator or skimmer. Cook down liquid by about 1/3, and serve sauce with meat and onions.


I used a standard 3 1/2 quart Crockpot for this recipe.

I used Szeged Steak Rub and Fini Balsamic Vinegar but there are many good brands.

This recipe created by Kalyn, and it’s been hugely popular on the site!

All images and text ©

Low-Carb Diet / Low-Glycemic Diet / South Beach Diet Suggestions:
With the fat trimmed well and served with the onions, this Low-Carb Balsamic and Onion Pot Roast is suitable for any phase of the South Beach Diet, and it would also be suitable for most other low-carb eating plans, which may not care about trimming the fat! Balsamic vinegar and onions both have some carbs, so concentrate on the meat and go easy on the sauce if you’re making this for a low-carb diet.

Find More Recipes Like This One:
Use the Diet Type photo index pages to find more recipes suitable for a specific eating plan. You can also Follow Kalyn’s Kitchen on Pinterest to see all the good recipes I’m sharing there. Click for Slow Cooker / Pressure Cooker Recipes on my other site!

Nutritional Information?
If you want nutritional information for a recipe, you can sign up for a free membership with Yummly and use the Yum button on my site to save the recipe and see the nutritional information. Another option is entering the recipe into this Recipe Nutrition Analyzer, which will calculate it for you.

Low-Carb Balsamic and Onion Pot Roast (and How to Make Pot Roast in a Slow Cooker) found on KalynsKitchen.com

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168 comments on “Low-Carb Balsamic and Onion Pot Roast (How to Make Pot Roast in a Slow Cooker)”

  1. What is the calorie intake for this recipe?

    • I am currently not able to add nutritional information to the site. More than a year ago I switched my site to WordPress, which created the need to edit by hand to add more than 2,000 recipes to the preferred format for google. I have been working on that (with three assistants) for more than a year, so there is no possibility of me being able to calculate nutritional information until that project is completed. And I know that once I start doing nutrition info on one recipe people will expect to see it on every recipe, which is why I have decided to keep these two projects completely separate.

      If you look after the recipe itself, I give two links (where it says “Nutritional Information”) for suggestions of two ways to get that information. That’s all I am able to do at this time.

  2. The crockpot and Instant Pot are my new best friends during renovations! I can’t wait to try your fabulous pot roast!

  3. Such a helpful post! That potroast looks SO TENDER!

  4. Pingback: The BEST Instant Pot or Slow Cooker Roast Beef Dinners - Slow Cooker or Pressure Cooker

  5. Wow, wow, wow!! This is a phenomenal recipe! Soooooooo delicious though I don’t know how low carb it is after we ate ALL the onions in one meal! 🙂

    I followed the recipe exactly cooking it in my 5 in 1 pot…starting it in the slow cooker for 6 hours and finishing it off by pressure cooking because it would have still needed a couple of hours. It was melt in your mouth tender and had fantastic flavour. Thanks so much…this is going on the permanent rotation!

  6. Pingback: 25 Low-Carb Slow Cooker Dinner Recipes Your Family Will Love

  7. I want to try it now. Thank you!

  8. I have some venison to use up. Do you think this recipe would work?

  9. This was delicious!! I used a creole seasoning on the meat, so it was kind of spicy. Small can of tomato purée. Deglazed the pan with some of the balsamic vinegar mix. Added carrots. Couldn't be better. Thank you!!

  10. I'm not on south beach but I know a good recipe when I see one. I made this exactly as instructed until the end. The day before serving I separated the meat, onions and remaining liquid and refrigerated over night. Next day skimmed the fat off the top and with an immersion blender mixed half of the onions into the liquid to make a sublime gravy. Served the remaining onions on the side with sautéed mushrooms. May never use another pot roast recipe. Perfection. Thank you so much.

  11. Looks like a good one.

  12. This was soooo good. Cooking down the juices from the crockpot was the finishing touch.

  13. After years of trying "new" pot roast recipes, none could ever beat my tried-n-true original. But, this turned out perfectly and the flavor was out of this world! I only wish I had made more gravy at the end, it was so incredibly good. Thank you, Kalyn!!! I am so glad I stumbled across your blog.

  14. Sharon, so glad you're enjoying the recipes!

  15. Wow. My husband and I are just finishing our SBDphase 1, and we couldn't have done it without all your fabulous recipes, Kalyn! This pot roast is just utterly fantastic – probably the best thing I've eaten in months, let alone just on South Beach!! I've made a document containing all the recipes I used for phase 1, and about 3/4 of them are Kalyn's Kitchen! I made the pot roast exactly as you wrote (you've never steered me wrong!) but served with some broccoli and toasted spaghetti squash – I felt like I was eating a wonderful roast, not at all "diet food".

  16. So glad to hear you liked it!

  17. Kalyn, thank you so much for the recipe! I was looking for a good low carb crockpot recipe, and came across this. A HUGE hit in my household tonight! Definitely going on the "will make again for sure" list.

  18. Sarah, so glad you liked it, and thanks for the pin!

  19. Oh my STARS, I made this last night, and it's gooooooooooooooooooood. So delicious. I did add the carrots (about half a bag of baby carrots). I didn't have plain tomato sauce, so I substituted some Classico Cabernet Marinara, and I used Grill Mates Steak rub. I wondered if those flavors would go together, and they DID. Thank you so much! This recipe has been shared AND "Pinned."

  20. Helen, so glad you enjoyed it!

  21. Hi Kalyn,
    Made this for dinner tonight in my crockpot. It was soooo good!! A new favorite. Another wonderful recipe.

  22. Katherine, thanks for that nice comment!

  23. Made this last night as I was looking for something different than the usual onion mix/carrot/potatoes pot roast. WOW! Delish. Mine came out a just a touch dry, but I take 100% of the blame for that. I got stuck at work so instead of the recommended 6-8 hours mine was a little more than 9. But OH MY GOSH those onions! Perfect!! I could just have had a crock pot full of those. Amazing! This will definitely be going on the monthly dinner rotation! Oh, and if anyone reading this has NOT made Kalyn's stuffed peppers, stop what you are doing and go make them immediately. Still one of my all time favorite recipes. Thanks Kayln!

  24. Colleen, I think that should work out fine. Hope you enjoy it!

  25. I was looking for a crock pot roast beef recipe on Pinterest and stopped at your picture! I've read the ingredients and all these great comments and can't wait to try it. I plan to use a 6+ lb roast as I'm feeding 4 strapping men and 2 women. Should I just double all the ingredients and figure less is more when in doubt?

  26. Genna, of course you *can* cook it on high for less time, but the meat will be more tender when it's cooked for a longer time on low. Probably still good though.

  27. Hi, I can't wait to try this recipe! Can I also cook it on high for lesser time?

  28. This was our dinner tonight. Yummy! Thanks!

  29. I just use plain yellow onions, but I think sweet onions would be fine.

  30. This looks absolutely amazing! I've only used my crock pot a couple of times for fondue & pulled pork recipes, and have been looking for other tasty recipes to try. My mom made balsamic onions in the oven one Thanksgiving and they were incredible, so I can't wait to try this!

    What kind of onions do you suggest for this recipe? I love Walla Walla, or sweet Vidalia onions, but I'm wondering if they would be too sweet?


  31. So glad people are still enjoying this!

  32. Just finished my plate full. Holy s*it. best tasting roast I've had!! Roast if my bf's favorite so I have been trying to perfect a recipe for 3 years, but I think I can stop now 😉 thanks!

  33. Got this in the crockpot as I type…the onions smell wonderful! I can't wait till it's done! We're having baked potatoes with it so the onions and sauce will be a great topping for them!

  34. I think either way would work, since you want the meat to be complete thawed before you make the recipe. If you're short on time in the morning though, I'd brown before freezing.

  35. This recipe sounds delicious! I got the link for this recipe off of "The Test Kitchen of Melissa Fallis." She has an entry about freezer crockpot meals. In her entry, she buys ingredients for 5 meals, freezes 4, and makes this one. But I was wanting to freeze this one too. Should I brown the roast before I freeze it? Or remove it from the freezer, brown and thaw, and then put it in the crockpot? I am not sure what to do! Thank you in advance for your advice!

  36. Gerry, reduce means to cook the liquid on the stove until it's partly evaporated. It makes the flavors stronger. (Google can often answer questions like this too if you get stuck again on a recipe.)

  37. great looking recipe. i am not a new cook but i never understood some of the lingo like reduce 1 cup to half cup is this a duh question or what?

  38. I have a bit of an addiction to vinegars! I have half a pantry full of various vinegars; different prices, flavors, etc. I have found that the acidityand sweetness varies between bottles. All balsamics are not created equal! Thank you Kalyn for such an amazing site!

  39. Tesla, did you add the full amount of liquid, both stock and water? If so I would probably use less vinegar next time.

  40. Well I made this recipe tonight and I was very excited about it. It smelled so yummy, but when I tasted it it was very tart and strong. I don't usually cook with balsamic vinegar, but I didn't expect it to be so very sour. I decided to add some brown sugar to help mellow it out and that helped, but the sweet, tart and acidic combo just really suit my taste. I did enjoy the overall flavor, so I may try and make this again and tweak it a little more to my taste.

  41. Hi Kalyn, found this recipe on Pinterest. Just wanted to trying something new instead of the same old meat, carrots and potatoes. I definitely think this is the one and I am looking forward to making it in a couple days!

  42. Hey Kalyn! I made this roast a few weeks ago and finally wrote up my own blog post about it. Delicious recipe! Thanks!


  43. I browned both sides well. I think you can tell from all the comments here that the post roast is going to get tender. Cook it for the rest of the time without lifting the lid and I bet it will be great.

  44. So I'm 4 hours into the 8 hour roast and I am very nervous. My hubby and I cut the pieces down, since that is what the picture shows and I "browned" the meat but it looks SUPER tough right now. I'm staring to think up a back-up dinner plan because I don't see how this will tenderize from where it is at right now. What did I do wrong? I didn't cook the meat through, but how would you define "browning well"… I browned top and bottom.

  45. As far as I know, carrots are still not permitted for phase one due to the sugar content. The newest book that has a foods list (South Beach Diet Supercharged) has them on "Foods to Avoid" for Phase One.

  46. Why not carrots? Are they not permitted now in Phase I?

  47. Kalyn,
    My kids absolutley loved the roast! They ate it with vigor and smiles.
    I made it without the steak seasoning just a smidge of pepper and garlic salt in its place. Then instead of reducing the broth used the broth anf leftover meat as a vegtable soup base. It was a hit.
    So thank you for sharing this recipe it made two delicious meals for my family.

  48. Thanks, so glad you liked it!

  49. I always hated pot roast, but I figured I would try this recipe since it seemed simple and didn't include many ingredients. IT IS HANDS DOWN THE BEST POT ROAST I HAVE EVER HAD. It was so easy to make, and I think it's now my favorite meal. Thank you!

  50. Jeanny, so glad to hear you have been enjoying the recipe that much!

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