Mediterranean High Protein Breakfast Casserole
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This low-carb, nutrient-dense, high protein breakfast casserole is cheesy, colorful, and absolutely packed with flavor. Eggs, ground turkey sausage, three kinds of cheese and milk provide lots of protein to keep you satiated. Best of all, it works great for meal prep or as a freezer meal. Check out even more of our High Protein Meal Prep Ideas!
This post is created in partnership with Hy-Vee Columbia.
Why I Love This Recipe
- Flavor Combo: I absolutely adore this veggie combination in all kinds of dishes, but especially in this low-carb, high protein breakfast casserole. The feta lends a salty, slightly tangy bite that balances the sweetness of the red bell peppers perfectly, while the turkey sausage contributes a little kick of heat.
- Meal Prep: Either make it ahead for the week and store in the fridge (up to 5 days) for quick breakfasts and lunches, or prep several at a time as a freezer meals for later.
- Makes You Feel Good: What’s magical about this particular recipe is not only do you feel like you’re eating a luxurious dish, but it’s sooo good for your body too. It’s packed with produce (red peppers, spinach, and garlic), and protein (lean turkey sausage, eggs, cheese, and milk) and low in sugar and carbs, too. Hooray!
- Extremely Well Tested: I tested this breakfast casserole over 10x and in three different kinds of dishes (glass, ceramic, and non-stick metal). You can be assured that it works as written.
Ingredients
These simple, flavor-packed, nutrient-dense ingredients add up to one tasty casserole that leaves you satiated and feeling good. You’ll find all these wholesome ingredients at your local Hy-Vee (Columbia).
Ingredient Notes:
- Ground turkey breakfast sausage – You can use pork breakfast sausage instead or you can omit the sausage. If you leave it out, the casserole will cook faster so keep a close eye on it.
- Frozen spinach – It’s important to thaw it and squeeze out excess water. Place the thawed spinach in an older kitchen hand towel and twist it hard or just squeeze it in your hands over the sink. A substitute is baby spinach or stemmed kale, roughly chopped and sauteed until wilted.
- I used three different types of cheese in this recipe and highly recommend using all three as directed. They add subtle flavor and textural differences.
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Step-by-Step Instructions
You can find the full recipe in the printable recipe card at the bottom of this post.
Cook Sausage
Brown the turkey sausage over medium-high until no longer pink, breaking it up with a wooden spoon as it cooks. Sprinkle the crumbled meat in the bottom of the casserole dish.
Cook Red Pepper & Garlic
Saute red pepper with salt, and pepper. Add the garlic at the end of the cook time, and be careful not to burn it. Spread the red bell pepper mixture over the turkey sausage.
Layer Ingredients
Sprinkle the spinach over the peppers. Finally, top with 1/2 cup mozzarella cheese and then all the feta cheese.
Add Egg Mixture
Whisk together the eggs, milk, Parmesan, and a 1/2 teaspoon ground black pepper. Pour egg mixture over the top of the casserole.
Get Ready to Bake
Sprinkle the remaining 1/4 cup mozzarella cheese over the top last of all. (Freezing instructions begin here.)
Bake & Serve
Bake for 40-50 minutes (keep a close eye on it!), rotating the pan around once. Casserole is done when the top looks puffy and is slightly golden brown and the center just barely jiggles when you give a gentle shake of the pan. You can also insert a knife in the middle and if it comes out clean, it’s done.
Let cool slightly. Then slice and serve warm. Leftovers can be stored in the fridge and used for breakfast and lunches for up to 5 days.
How to Freeze a High Protein Breakfast Casserole
Based on years of recipe testing, we’ve found that the best way to prep a recipe like this for the freezer is to freeze it BEFORE baking. Here’s how…
To Freeze: Put casserole together (through Step 5) but do not bake. Cover tightly with plastic wrap and/or foil. Carefully place in freezer.
To Prepare: Thaw about 24 hours in the refrigerator. Bake according to directions.
That being said, you can freeze individual portions after baking it. Let the casserole cool completely, cut into small portion sizes, wrap each piece in plastic wrap, and place in a freezer bag. Just be sure to thaw them in the fridge and warm in 20-second increments in the microwave so it doesn’t dry out.
FAQs
I tested this recipe in non-stick metal, ceramic, and glass 8×8-inch pans. All three work, but glass and ceramic can be tough to clean later. They also don’t cook quite as evenly.
The non-stick metal pan was by FAR my favorite way to bake this and had the best results. It didn’t stick to the sides and baked very evenly. I used this Caraway 9×9-inch square pan which I highly recommend investing in!
Yes, I’ve tested this without the sausage. It still tastes great, but it will bake about 10 minutes less than the recipe calls for so keep an eye on it.
After baking, you can store this high protein egg casserole in the fridge for up to 5 days.
More High Protein Recipes
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Mediterranean High Protein Breakfast Casserole
A nutrient-dense, low-carb, high protein breakfast casserole that’s cheesy, colorful, and absolutely packed with flavor. Best of all, it works great for weekly meal prep or as a freezer meal.
Ingredients
- Butter (for greasing the pan)
- 2 teaspoons olive oil or avocado oil
- 1/2 pound ground turkey breakfast sausage (sub: pork breakfast sausage)
- 1 large red bell pepper, cored, seeded, and diced
- Pinch of red pepper flakes
- Salt and pepper
- 2 garlic cloves, minced
- 5 ounces (half package) frozen spinach, thawed and squeezed of all excess moisture (sub: 4 packed cups baby spinach or stemmed kale, roughly chopped and sauteed until wilted)
- 3/4 cup shredded mozzarella cheese, divided
- 1 cup (4 ounces) crumbled feta cheese (crumble any large chunks)
- 10 large eggs
- 1/2 cup grated Parmesan cheese
- 1/2 cup milk
Before You Begin! If you make this, please leave a review and rating letting us know how you liked this recipe! This helps our business thrive & continue providing free recipes.
Instructions
Make It Now:
- Preheat oven to 350° F. Grease an 8×8- or 9×9-inch casserole dish well with butter (it works better than cooking spray!). (See Cooking Notes about different pan materials.)
- In a medium-sized skillet, heat 1 teaspoon oil and cook the turkey sausage over medium-high until no longer pink, breaking it up with a wooden spoon as it cooks. Drain off any grease. Sprinkle the crumbled meat in the bottom of the casserole dish.
- Add another teaspoon of oil, if needed, and the red bell pepper to the pan and saute just until soft, about 4-5 minutes, seasoning with a pinch of red pepper flakes and lightly with salt and black pepper. Add the garlic at the end of the cook time, stirring around for about 30-60 seconds. Be careful not to burn the garlic. Remove from the heat.
- Spread the red bell pepper mixture over the turkey sausage. Sprinkle the spinach over the peppers. Finally, top with 1/2 cup mozzarella cheese and then all the feta cheese.
- In a medium mixing bowl, whisk together the eggs, Parmesan, milk, and 1/2 teaspoon ground black pepper. Pour egg mixture over the top of the casserole. Sprinkle the remaining 1/4 cup mozzarella cheese over the top last of all. (Freezing instructions begin here.)
- Bake for 40-50 minutes (keep a close eye on it!), rotating the pan around once. Casserole is done when the top looks puffy and is slightly golden brown and the center just barely jiggles when you give a gentle shake of the pan. You can also insert a knife in the middle and if it comes out clean, it’s done.
- Let cool slightly. Then slice and serve warm. Leftovers can be stored in the fridge and used for breakfast and lunches for up to 5 days.
Freezer Meal Instructions:
To Freeze: Put casserole together (through Step 5) but do not bake. Cover tightly with plastic wrap and/or foil. Carefully place in freezer.
To Prepare: Thaw about 24 hours in the refrigerator. Bake according to directions.
Notes/Tips
- The non-stick metal pan was by far my favorite way to bake this and had the best results. It didn’t stick to the sides and baked very evenly. I used this Caraway 9×9-inch square pan which I highly recommend investing in!
- It’s super important not to overcook this casserole and it can go fast. So check it on the front end of the cooking time and keep checking every few minutes. It’s better to remove it when it appears just slightly underdone in the middle because it will carry-over cook while it sits. The test is if a knife/fork inserted into the middle comes out clean.
- If you made this ahead and it’s cold from being in the fridge, either set it out on the counter for 30-60 minutes to come to room temp before baking and just know that it will take a little longer to bake if it’s chilled.
- Leftovers will keep well for up to 5 days in the refrigerator. Gently reheat in the microwave or oven. You can freeze leftovers (after they fully cool), but it may lose some of it’s moisture and adversely affect the texture when you thaw and rewarm. Be sure to thaw in the fridge and then gently reheat.
- If you want to omit the sausage, you can. It will bake about 10 minutes faster, so keep an eye on the casserole.
- Place thawed spinach in an older kitchen hand towel and twist it hard to squeeze out excess moisture.
- Want more high protein recipes? Check out our round up of High Protein Slow Cooker recipes.
Photos and video by Whitney Reist of Sweet Cayenne.
Made this tonight. Doubled it and froze one pan. I left out the feta for my three picky guys and sprinkled it on my own serving. Two out of my three picky guys ate it!
Hi Morgan! Thanks for taking the time to leave a review and for telling us how you handle this recipe with your picky guys. Glad to hear it was consumed by 2 of 3 of them. (And glad you didn’t miss out on the tanginess of the Feta!)
This was a huge hit at my house and will become a regular breakfast staple for us. It has mega flavor and love the texture as well!
Thanks for taking the time to leave a review Whitney!