Kalyn's Kitchen

Mushroom, Green Pepper, and Feta Breakfast Casserole

Make this delicious Mushroom, Green Pepper, and Feta Breakfast Casserole on the weekend and eat it all week! And this low-carb breakfast casserole is also meatless and gluten-free. 

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Mushroom, Green Pepper, and Feta Breakfast Casserole finished casserole with serving plates and garnishes

It’s been more than ten years now since I started on my personal journey of carb-conscious eating, and if I had to pick one thing that’s helped me to stick with lower-carb eating, it would be low-carb recipes that can be made on the weekend and then reheated during the week. And there’s no doubt that Low-Carb Breakfast Casseroles would top my list of things to make every weekend. Just taking a few minutes to get a breakfast casserole like this into the oven gives me an easy breakfast that just takes a few minutes to reheat, and gets my week off to a good start.

This Mushroom, Green Pepper, and Feta Breakfast Casserole is something I first made years ago, and this combination for a meatless breakfast casserole is still one of my favorites. When I first made this recipe I liked using 18 eggs for a breakfast casserole like this, but now I prefer more veggies and cheese and a little less egg. Breakfast casseroles are a great way to use leftover vegetables, so if you have anything in the fridge that might go well with mushrooms, bell peppers and feta, go ahead and throw it in! And I think this type of dish is a great Meatless Recipe for dinner as well!

Before you make this you may want to read Low-Carb and Keto Breakfast Casseroles which has instructions for different sizes of pans and ingredient options for this type of breakfast casserole, as well as 15+ of my favorite low-carb breakfast casserole recipes.

What ingredients do you need for this recipe?

  • sliced mushrooms
  • green bell pepper
  •  olive oil
  • crumbled feta
  • Spike Seasoning (affiliate link), or other all-purpose seasoning blend
  • fresh ground black pepper to taste
  • eggs
  • green onions

Low-Carb Mushroom, Green Pepper, and Feta Breakfast Casserole process shot collage

Steps for making this recipe:

(Scroll down for complete printable recipe including nutritional information:)

  1. Preheat oven and spray casserole dish with non-stick spray or olive oil. (I used a dish that was 10″ x 14″ but anything close to that size will work.)
  2. One at a time, saute sliced mushrooms and then chopped bell peppers and layer the veggies in the casserole dish.
  3. Crumble the Feta cheese over the vegetables.
  4. Then beat the eggs with Spike Seasoning (affiliate link) and black pepper and pour over the vegetable-cheese mixture.
  5. Sprinkle with green onions if using. I give it a little stir with a fork to get the veggies evenly distributed in the eggs. 
  6. Bake in a preheated over at 375F/190C for 35-45 minutes, or until the eggs are set and the top is starting to lightly brown.
  7. Serve hot. I love this with a dollop of sour cream.

More Tasty Ideas for a Low-Carb Breakfast:

Twenty Favorite Low-Carb Breakfast Recipes ~ Kalyn’s Kitchen
Instant Pot Keto Breakfast Casserole ~ All Day I Dream About Food
Low-Carb and Keto Breakfast Recipes Your Family Will Love ~ Kalyn’s Kitchen
Sausage, Spinach, and Feta Frittata ~ I Breathe I’m Hungry
Baked Eggs Skillet with Avocado and Spicy Tomatoes ~ Kalyn’s Kitchen
Broccoli, Mushroom, Egg, and Cheese Breakfast Casserole ~ The Perfect Pantry
Baked Eggs and Asparagus with Parmesan ~ Kalyn’s Kitchen

Mushroom, Green Pepper, and Feta Breakfast Casserole thumbnail photo

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!

Mushroom, Green Pepper, and Feta Breakfast Casserole thumbnail photo

Mushroom, Green Pepper, and Feta Breakfast Casserole

Yield 8 servings
Prep Time 20 minutes
Cook Time 40 minutes
Total Time 1 hour

Make this Low-Carb Mushroom, Green Pepper, and Feta Breakfast Casserole on the weekend and eat it all week!


  • 8 oz. sliced mushrooms
  • 1 large green bell pepper, chopped
  • 2 tsp. olive oil, to saute mushrooms and green peppers
  • 1 cup crumbled feta (or more, to taste)
  • 1 tsp. Spike Seasoning (see notes)
  • fresh ground black pepper to taste
  • 14 eggs
  • 3 green onions, sliced (optional)


  1. Preheat oven to 375F/190C. Spray 10 X 14 glass casserole dish with olive oil or non-stick spray. (Any dish that’s close to this size will work.)
  2. Wash mushrooms if needed and cut into thick slices.
  3. Cut out stem part of the green pepper and chop into pieces about 3/4 inch square.
  4. Heat non-stick frying pan to medium high, add small amount of olive oil, and saute mushrooms 4-5 minutes, until softened and starting to brown. Spread mushrooms in bottom of casserole dish.
  5. Add a bit more olive oil to frying pan if needed, and saute chopped green peppers until softened and partly cooked. Layer peppers over mushrooms.
  6. Crumble feta cheese over top of mushroom-pepper mixture. Season with Spike Seasoning (affiliate link) and black pepper. (Don’t add salt because Feta cheese is salty enough.) Sprinkle with sliced green onions if using.
  7. Beat the eggs until yolks and whites are well-combined and pour over mushrooms, peppers, and feta. Use a fork to gently stir the mixture so veggies and cheese are well-distributed in the eggs.
  8. Bake 35-50 minutes, or until casserole is firmly set and top is slightly browned.
  9. Serve hot. I like to eat it with a dollop of sour cream on top.


Spike Seasoning (affiliate link) is optional, but highly recommended; use another all-purpose seasoning if you don't have Spike.

Breakfast casseroles like this can be stored in the fridge for at least a week and reheat very well in the microwave or in a pan on top of the stove. If you’re heating in a microwave, be careful not to heat too long or the eggs will get rubbery.

Recipe created by Kalyn.

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 204Total Fat: 14gSaturated Fat: 6gUnsaturated Fat: 7gCholesterol: 342mgSodium: 488mgCarbohydrates: 6gFiber: 1gSugar: 3gProtein: 15g

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.

If you make this recipe I'd love to hear how it turns out. Leave a star rating or share on social media with the hashtag #KALYNSKITCHEN, thanks!

Low-Carb Diet / Low-Glycemic Diet / South Beach Diet Suggestions:
Mushroom, Green Pepper, and Feta Breakfast Casserole is a perfect breakfast for any phase of the original South Beach Diet or any type of low-carb or low-glycemic eating plan.

Find More Recipes Like This One:
Use Breakfast Recipes to find more recipes like this one. Use the Recipes by Diet Type photo index pages to find more recipes suitable for a specific eating plan. You might also like to Follow Kalyn’s Kitchen on Pinterest to see all the good recipes I’m sharing there.

Pinterest image of Mushroom, Green Pepper, and Feta Breakfast Casserole

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    41 Comments on “Mushroom, Green Pepper, and Feta Breakfast Casserole”

  1. Pingback: Keto Deals and Recipe Ideas at Aldi (week of 6/13) – Keto on a Dime

  2. Thanks Linda, glad you like it. And I'm afraid comment moderation is something I can't avoid. Seems like if I open comments up, I get over-run with spam comments.

  3. It looks scrumptious! Thanks so much for sharing. I also moderate comments on my blog. 🙂

  4. I’ve been scared of the idea of feta with eggs, but I finally sprinkled some on my scrambled eggs last week, and it was delicious. So, I’m finally making one of your egg dishes with feta this week. I am hopping back on Phase 1 to get ready for Thanksgiving (although this diet has turned my husband into a bean pole, and he should probably stay on phase 3…)

  5. This looks fab….I’m always looking for new recipes for breakfast! Thanks Kalyn

  6. I love that this is so much veggie! This is my idea of the perfect breakfast make it ahead! I know I’ll be doing this one. And it look so easy to be putting it together.

  7. Kevin, thanks.

    Mrs. L., you can use any type of cheese. Also there are other options in the recipe archives with different cheese. One of my favorites is broccoli with cheddar cheese.

  8. Though I love feta, the husband doesn’t. I could probably substitute other cheese in this? And maybe add some salt?

  9. I like the sound of a breakfast casserole and this one looks tasty.

  10. Jenni, it really does stay good for quite a long time. I ate some of this one today and I made it 8 days ago. It was just fine. You can freeze it too, but I do think it’s better when it hasn’t been frozen.

  11. This sounds delicious!

    How long will it stay fresh in the refrigerator? I’m the only egg eater in the family!

    Thanks for all your yummy recipes!

  12. Dina, thanks. Hope you like it.

    Mrs. G., yes I think you could eat this for breakfast, lunch, or dinner.

    Hi Freddie’s Mom,
    I can imagine that green peppers would be hard to sneak past a kid. Try some other vegetable combination. Broccoli/cheese is good in this. I don’t think I can manage some kind of vegetable project with the class because I just switched to third grade this year and I’m barely keeping my head above water with the blog and a new curriculum. Plus I don’t teach health, there is a special teacher, so it would be hard to fit it into the day. Thanks for thinking of me though.

  13. Kalyn – This is the first time I have read of a breakfast casserole and I wll try this with the kids. I might substitute the peppers aas Freddie finds them a little off-putting!
    Fancy doing some kind of veggie-recipe hook up with your third grade kids and one boy in London?

  14. Breakfast…it’s what’s for dinner! Thank, Kaylen

  15. I’m going to make this for breakfast this week. Really great idea.

    Thanks for the idea.

  16. Susan, this should be perfect for you. Just throw in whatever veggies are in growing at that time, chard, spinach, zucchini, peppers, just about any vegetable would be good.

    Chigiy, I had about given up on peppers before this year, but now I’m sure I will grow them every year. I just hope my pepper curse doesn’t come back!

    Nabeela, thanks. Hope you like it.

  17. I’ve been searching for a veggie-heavy breakfast casserole for days. I wanted a tried and tested recipe….and this seems perfect. I’ll probably try it with red peppers..I agree with you about them being milder nand tastier. Thanks for the recipe!

  18. Next year I’m going to grow my own green peppers, because I agree. I am not a big fan of store bought peppers, but home grown are yuuummmmy.
    This looks good.
    I love breakfast casseroles.

  19. This looks fantastic. I always forget about breakfast casseroles which is crazy because we’re never without fresh eggs (I bought duck eggs from some neighbors last week!), and I’m always wandering into the kitchen looking for something (besides cheese & crackers) to eat now. This is the perfect kind of food to have on hand in the fridge. Thanks for the recipe–and the reminder! : )

  20. Lucette, isn’t that interesting that we both had the pepper curse? And this year my peppers have been gorgeous!

    ETB, good for you! This is a great “before school” breakfast. It will keep you going until your (very short) lunch break!

    Hooray, this anonymous comment is from my friend Robin who has just gotten her internet connection hooked up. I see she knows how to get in touch with me!