This Low-Carb Turkey Casserole is such a delicious option for leftover turkey, but it’s equally delicious if you make it with chicken. And this casserole is popular all year, so lots of people must be making it with chicken!

PIN Low-Carb Leftover Turkey Casserole to try it later!

Low-Carb Turkey Casserole with Mushrooms, Mozzarella, and Cauliflower Rice close-up photo

Tomorrow is Thanksgiving and I’m going to my sister Pam’s house this year, so I might not even get any leftover turkey. But if I did I’d definitely be making this Low-Carb Turkey Casserole on the day after Thanksgiving! Out of all my Recipes for Leftover Turkey this is the leftover turkey recipe I’ve made the most!

I’m proud of this recipe and with good reason because I tried multiple times with Kara to come up with a tasty casserole that used Cauliflower Rice (affiliate link) instead of rice, and the first three times we ended up with a casserole that tasted okay but was really watery. For this keeper version we skipped the turkey stock and used a thick sauce of sour cream, mayo, Dijon, Parmesan, Mozzarella, and spices, and it held the mixture together with just enough cheesy creaminess to make it good!

Of course you don’t have any leftover turkey yet, but you can definitely make this tasty casserole with chicken any time of year. This is a pretty brown dish, so my apologies that the step-by-step photos are all so colorless, but please: Make. This. Recipe. You will not regret it!

What ingredients do you need?

  • chopped cauliflower
  • Cremini mushrooms
  • cooked leftover turkey or chicken
  • onion
  • Olive Oil (affiliate link)
  • Dried Thyme (affiliate link)
  • Poultry Seasoning (affiliate link)
  • salt and fresh-ground black pepper to taste
  • coarsely grated Mozzarella
  • sour cream
  • mayo
  • Dijon mustard
  • coarsely grated Parmesan cheese

Can you use frozen cauliflower rice for this recipe?

I haven’t made this with frozen cauliflower rice. And although I think it will probably work here, I prefer freshly chopped and cooked cauliflower in a recipe that is going to bake for this long. (If anyone tries frozen cauliflower rice and thinks it works great, let us know in the comments.)

What if you don’t have leftover turkey for this turkey casserole?

This casserole can definitely be made with rotisserie chicken or other leftover cooked chicken!

Want more low-carb recipes for using leftover turkey?

Check out Low-Carb Recipes for Leftover Turkey for more tasty recipes like this one.

Low-Carb Turkey Casserole with Mushrooms, Mozzarella, and Cauliflower Rice process shots collage

How to Make Low-Carb Turkey Casserole:

(Scroll down for complete printable recipe with nutritional information.)

  1. Chop up the cauliflower and then pulse in a food processor or grate with a hand grater to make the small pieces of cauliflower. (More photos of how to do that on the recipe for cauliflower rice if you need them.
  2. If you want to substitute frozen cauliflower rice I’d use about 3 cups, but I do think the fresh cauliflower might hold up better in this.
  3. Wash and dry mushrooms and cut into thick half-slices.
  4. Cut up the leftover turkey (or chicken) into bite-sized pieces.
  5. Mix together the sour cream, mayo, Dijon, dried thyme, Poultry Seasoning, 1 cup of Mozzarella cheese, and the Parmesan to make the thick sauce.
  6. Cook the mushrooms until they’re a little browned; then make a layer of mushrooms in the casserole dish.
  7. Then cook the onions until they’re starting to brown and make a layer of onions in the dish.
  8. Add a little more oil and saute the cauliflower rice until it’s starting to soften and slightly brown, adding the other teaspoon each of dried thyme and Poultry Seasoning to the rice for the last few minutes of cooking time. (Frozen cauliflower rice will cook a little more quickly.)
  9. Add the rice to the dish with the onions and mushrooms.
  10. Then add the diced turkey (or chicken), and gently stir so the ingredients are mixed.
  11. Spread the sauce mixture over the top of the casserole; then use a plastic spoon to gently mix it so the ingredients are fairly well combined with the sauce.
  12. Top the casserole with the rest of the Grated Mozzarella.
  13. Bake at 375F/190C until it’s bubbling and nicely browned, about 40 minutes.
  14. Let the casserole cool about 5 minutes and then cut into 8 pieces and serve. This can also be kept in the fridge and reheated later.

Low-Carb Turkey Casserole finished casserole in baking dish and one serving on plate

Low-Carb Chicken Casseroles you can make with Leftover Turkey:


Weekend Food Prep:

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

Low-Carb Turkey Casserole
Yield: 8 servings

Low-Carb Turkey Casserole

Prep Time 45 minutes
Cook Time 40 minutes
Total Time 1 hour 25 minutes

This delicious Low-Carb Turkey Casserole has mushrooms, Mozzarella, and cauliflower rice can be made with turkey or chicken.



  • 6 cups chopped cauliflower (see notes)
  • 1 pound Crimini mushrooms, washed and sliced
  • 4 cups cooked leftover turkey or chicken
  • 1 onion, chopped
  • 2 T olive oil, divided (more or less depending on your pan)
  • 1 tsp. dried thyme
  • 1 tsp. dried Poultry Seasoning
  • salt and fresh-ground black pepper to taste
  • 1 cup coarsely grated Mozzarella (or more)

Sauce Ingredients

  • 1 cup sour cream
  • 1/2 cup mayo
  • 2 T Dijon mustard
  • 1/2 tsp. dried thyme
  • 1/2 tsp. dried Poultry seasoning
  • 1 cup grated Mozzarella
  • 1/4 cup coarsely grated Parmesan cheese


  1. Spray a large glass or crockery casserole dish with olive oil or non-stick spray.  (I used a dish that was 10″ x 13″ but any size that’s close to that will work.)
  2. Preheat oven to 375F/190C.
  3. Chop up enough cauliflower to make 6 cups of small cauliflower pieces. Then use a food processor with a steel blade to pulse the cauliflower until it’s finely chopped, slightly larger then kernels of rice.  (See the recipe for cauliflower rice for more about how to do this.  You can also chop the cauliflower by grating it on the side of a box grater.)
  4. Use frozen cauliflower rice if you prefer, about 3 cups.
  5. Wash the mushrooms and cut into thick half slices.
  6. Dice the leftover turkey (or chicken) into bite-sized pieces.
  7. Mix together the sour cream, mayo, Dijon mustard, 1/2 tsp each dried thyme and Poultry seasoning, 1 cup grated Mozzarella, and 1/4 cup Parmesan to make the thick sauce mixture.
  8. Heat 2 tsp. olive oil in a large non-stick frying pan and saute the mushrooms over medium-high heat until they release their liquid, all liquid evaporates, and mushrooms are starting to brown.
  9. Put mushrooms in the bottom of the casserole dish.
  10. Add about 2 tsp. more olive oil and saute the onions over medium-high heat until they are softened and starting to brown.
  11. Put onions over the mushrooms in the casserole dish.
  12. Heat another 2 tsp. of olive oil and add the finely-chopped cauliflower.
  13. Cook over medium-high heat, stirring often, until the cauliflower is starting to soften and barely brown, about 3-4 minutes (or slightly less for frozen cauliflower rice).
  14. Add the 1 teaspoon each of dried thyme and Poultry Seasoning and cook about 1 minute more.
  15. Season the cauliflower rice with a little salt and fresh-ground black pepper; then put it into the casserole dish over the mushrooms and onions.
  16. Put the diced turkey into the casserole dish over the veggies and use a plastic spoon to combine the ingredients right in the dish.  (You can do this in a bowl if you prefer, but we were trying to get away without dirtying another dish!)
  17. Spread the sauce mixture over the top and then use the spoon to gently combine the ingredients with the sauce, until the ingredients are well mixed into the sauce.
  18. Wipe off the sides of the casserole dish with a paper towel if needed.
  19. Sprinkle with Mozzarella cheese and bake uncovered until the casserole is starting to bubble and the top is nicely browned, about 40 minutes.
  20. Let cool about 5 minutes; then cut into 8 servings and eat while hot.


You can also use about 3 cups frozen cauliflower rice for this recipe. I used Crimini (Baby Bella) mushrooms.

This kept amazingly well in the fridge for days, and can easily be reheated in the microwave or in a pan on top of the stove.  I’m guessing it freezes well, but I ate all my leftovers before I could freeze any.

Recipe created by Kalyn and Kara. 

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 472Total Fat: 33gSaturated Fat: 11gUnsaturated Fat: 20gCholesterol: 131mgSodium: 597mgCarbohydrates: 8.6gFiber: 3gSugar: 5gProtein: 33g

Nutrition information is automatically calculated by the Recipe Plug-In I am using. I am not a nutritionist and cannot guarantee 100% accuracy, since many variables affect those calculations.

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Low-Carb Turkey Casserole in baking dish with plates, forks

Low-Carb Diet / Low-Glycemic Diet / South Beach Diet Suggestions:
This Low-Carb Turkey Casserole would be suitable for low-carb and Keto eating plans. I would probably eat it for any phase of the original South Beach Diet, but I used full-fat sour cream, mayo, and Mozzarella for this and South Beach would recommend using reduced-fat dairy products.

Find More Recipes Like This One:
Use Casserole Recipes to find more recipes like this one. Use the Diet Type Index to find recipes suitable for a specific eating plan. You might also like to follow Kalyn’s Kitchen on Pinterest, on Facebook, on Instagram, on TikTok, or on YouTube to see all the good recipes I’m sharing there.

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