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. 

PIN this recipe to make it later!

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. Guess what! I’m emailing from my home laptop that I just hooked up myself (while on the phone for 45 min. with a very nice Canadian woman).

  2. It looks excellent and seems to be a great time-saving idea for busy people. I shall have to try it!

    I will be teaching myself before too long, so ideas like this will come in handy!


  3. This looks good enough for company!
    I had my 1st successful year with green peppers this year, too–trying to figure out why.

  4. Valli, we were writing our comments at the same time! I agree, Feta is wonderful in everything you could possibly imagine!

  5. Anh, me too. Love the combination.

    EMWK, thanks. You can make any variation that appeals to you.

    Christine, thanks.

    Ed, I think turkey would taste great in this.

    Sher, I never buy them in the store, but love the garden ones.

    Jasmine, there are no class size limits in Utah. Too many students to be able to afford that. But luckily most of the kids are pretty well-behaved and I have a lot of parent volunteers and an aide. Hope you like the breakfast casserole.

  6. Anything with feta has to be good!!!!

  7. yum!! I was checking my blog lines last night while waiting for my boyfriend to get off the phone and came across this recipe and while this mornings breakfast was reheated spinich and tomato frittata from yesterday before he had to run off to church — I am making this when I get back from the farmer’s market for breakfasts this week!

    Sorry to hear about the 28 kids — we just added a new kindergarten because all the classes were up to 24 and more were coming every day…I think our cap in 3rd grade is 26 before they add new classes.

  8. I love breakfast casseroles. They’re delicious and easy to assemble. And I can’t figure out why store bought bell peppers are often rather bitter. But, home grown oners don’t have that problem.

  9. Kalyn – You had me at “Breakfast Casserole”. That looks delicious. I can also imagine tossing in some shredded leftover turkey for yummy day-after-Thanksgiving turkey breakfast.

  10. I love this dish! Beautiful presentation.

  11. This is a great idea for extending meals into the week. I’ll have to keep this one in mind!

  12. This is a very nice dish for brunch Kalyn! Mushrooms and feta, one of my fav combo!

  13. Nika, glad to hear you are getting peppers. Your garden is so impressive. I want grow boxes!

    Rob, I have heard a little about square foot gardening, but don’t know much about it. thanks for the tip, I will check it out. Is this guy from Utah? I didn’t know that if he is.

    Messo, I agree, cook once and eat a few times. Thanks!

    Lydia, this is totally flexible, you can add just about anything. Well, maybe not fish!

    Katie, I confess, I do sometimes eat it in the car! But I try hard to eat at home.

    Pille, me too. We’re fellow Feta lovers!

    Janelle, I bet the farmers market peppers are also great. I do have an awfully cute class this year. There are just too many of them (28). But I’m doing ok and they seem to think I’m at least mildly amusing!

  14. Kalyn: I just printed this recipe and will try it this weekend! I agree, green peppers from the grocer are not my fave. But I am curious about yours from the garden! I will use some greens from our farmers’ market to make this, just to make sure…

    Hope you are well! And that you have a nice 3rd grade class this year.:) They are lucky to have you.

    Happy new school year!

  15. This contains some of my favourite ingredients, so I’d happily have this for breakfast/brunch. Or lunch or dinner 🙂

  16. You actually eat this for breakfast?
    I mean, I would love this for breakfast, but when I was working my breakfast was a muffin and a handful of dried fruit eaten in the car.
    I could have it now, though…naw, I’d have it for lunch with a glass of rosado!
    Anyway, it looks and sounds scrumptious!

  17. I love recipes like this, too. So flexible, so easy to make, so impressive when you serve them to friends.

  18. This is great…I also love dishes I can eat from for a few days…I can have homemade food but also save time! This is looking delicious!!!

  19. I have never come across the concept of a breakfast casserole before but I am sold! So practical to do the big cooking at the weekend and have portions to use in the week.

    This recipe also looks delicious, and as I am growing my own mushrooms this year (they were selling kits at the market last week) I will at least have one home grown ingredient to include in the dish…

    Kalyn, as you are in Utah, I was wondering if you have heard of Mel Bartholomew and his concept of Square Foot Gardening? As an avid gardener it might be worth you getting his book or checking out his website (www.squarefootgardening.com/). I believe he also runs courses locally.

  20. This looks so delicious, will have to give it a try! We FINALLY got a few green peppers too, we had the same problem you had.