Low Carb Breakfast Casserole (or Muffins)

5 from 13 votes

This low carb breakfast casserole is healthy, packed with veggies, less than 30 minutes and adaptable to whatever you have on hand. It’s a great make ahead, freezer friendly, breakfast on-the-go.

The eggs and veggies are baked in the oven and can be made into muffins or a casserole. Instructions for both are in the recipe.

one square of egg casserole with veggies topped with tomatoes

Casserole or muffin format? The muffins are super cute and make an awesome grab and go breakfast. But the casserole is easier I think, so you choose.

I just love the colors of the fresh veggies, especially the baby spinach. I don’t bother sautéing the vegetables before combining them with the egg mixture, but you can if you want for deeper flavor and less spongy eggs.

This low carb breakfast casserole is an easy recipe with simple ingredients. You can even make it in advance…which is great way to get a healthy breakfast on the table quickly on busy mornings.

What to expect

Versatility is the name of the game here for:

Ingredients: The core ingredients are eggs and cheese. The rest is pretty much up to your imagination. Veggies and/or meat.
Baking method: Bake in a single baking dish or as individual servings in a muffin tin. The egg casserole is similar to a frittata without the frying part.
How to enjoy them: Freshly baked, make ahead for meal prep or freezer option.

Nutrition

The dish is dairy free (if you add a dairy-free cheese), gluten free and perfect for a low carb or keto breakfast casserole recipe. I usually make a vegetarian version except when my son in law comes over.
This can be considered a healthy breakfast casserole with good protein from the eggs and cheese, good fiber and vitamins from the vegetables and some calcium from the cheese. It’s low carb and fairly low fat (as it’s baked in the oven).

Ingredients – tailored to your taste

cracked eggs in a bowl, spinach, bell pepper, parsley, grated cheese, green onion — Eggs, spinach, parsley, red pepper, grated cheese, green onion, seasonings

Variations to consider:

Here’s where you can pick and choose your faves or whatever you have on hand.

Vegetables: Use any of your favorite vegetables. I like green onions, fresh baby spinach and red bell peppers because of the color combination. Other good options are mushrooms, tomatoes with juices squeezed out, cooked sweet potatoes or zucchini. I suggest sautéing the mushrooms and zucchini first, though, because they have such a high-water content. Finely chop any vegetable you use.

Cheese: Use any combination of cheddar cheese, Monterey Jack, smoked Gouda, Swiss, Mozzarella or Pepper Jack cheese. You can also try feta cheese, goat cheese, parmesan cheese or ricotta.

Meat options: For a non vegetarian breakfast casserole, finely chopped cooked bacon, Italian sausage, breakfast sausage, chicken sausage and ham are all good options.

Herbs: Try fresh or dried basil, thyme, cilantro, oregano, parsley or dill.

Seasonings: You can add curry powder, garlic powder, taco seasoning, a pinch of smoked paprika, cayenne pepper, coriander or dried herbs. A tablespoon or so of olive tapenade would be amazing too if you like olives. I like to add 1/2 tsp of Dijon mustard to the egg mixture.

Step by step (for casserole and muffin format)

chopped veggies in processor bowl — Process veggies in a food processor until finely chopped. Include the cheese or add it after.

veggie egg mixture in bowl — Whisk eggs in a large mixing bowl. Add chopped veggie mixture with cheese and seasonings.

For a full-size casserole:

baked egg casserole in pyrex glass dish — Bake 17-19 minutes (for 7 x 11 pan/28×18 cm) or just until center no longer jiggles.

squares of egg casserole with veggies topped with tomatoes

For muffin cups:

unbaked veggie muffin cups — _{Follow first two steps above. Keep cheese for the topping. Grease a muffin tin or spray with nonstick cooking spray. Pour egg veggie mixture into greased muffin tins Add cheese on top of the casserole of muffins. Bake.}

6 baked veggie muffin cups in muffin containers — _{Follow first two steps above. Keep cheese for the topping. Grease a muffin tin or spray with nonstick cooking spray. Pour egg veggie mixture into greased muffin tins Add cheese on top of the casserole of muffins. Bake.}

Tip

Should you add milk to the eggs? No. You might be used to adding whole milk or heavy cream to your scrambled eggs, but it’s not the best way. Milk doesn’t make fluffy eggs (as I used to think). In fact, adding milk dilutes the flavor and makes the eggs rubbery.

Recipe FAQs

What are the best types of eggs to buy?

According to Food and Nutrition, conventional eggs are perfectly fine. Pasteurized eggs are nutritionally the same as regular eggs, but but likely safer with lower risk of salmonella. Organic eggs are not better, just different in the amount of nutrients supplied. Cage-free, free-range certified organic eggs and pasture-raised eggs are not likely healthier or better, but you would be supporting humane farming practices.

Why is my egg casserole spongy?

The sponginess in the egg casserole is due to the combination of moisture from the eggs and added vegetables. To reduce the natural spongey texture of eggs, you can: 1) add a small amount of flour or cornstarch (about a tablespoon in this recipe) to the egg mixture 2) whisk less air into the eggs 3) precook the veggies.

How long does breakfast casserole last in the fridge?

As long as it is kept in the fridge, covered tightly with plastic wrap, it should stay fresh for between 4-5 days.

What to serve with a breakfast egg bake

For breakfast, I like to serve the squares with chopped tomatoes and avocado or some berries.

If you’re serving this egg casserole as part of a weekend brunch buffet, here are a few complementary recipes for your buffet table:

apple French toast casserole
easy cinnamon buns (with a great shortcut)
marinated tomato salad
breakfast strata (with various fillings)
no-bake berry crumble
Montreal bagels
Homemade English muffins (easy step by step)
Dutch pancake recipe (also called German pancake)
easy potato skillet breakfast with ham
instant pot oatmeal recipe (with steel or rolled oats)

Shortcuts

Throw all the veggies you’re using into the processor to chop finely.
Buy pre-shredded cheese.
Buy pre-washed (and dried) fresh baby spinach.

Make ahead

The low carb breakfast casserole can be prepped the day before and baked the following day. Or it can be fully cooked and kept in the fridge for up to 4-5 days. It can also be frozen for 2-3 months in an airtight container or bag.
Instructions for all 3 options and reheating are in the recipe below.