High Protein Breakfast Casserole

Here’s a delicious, easy high protein breakfast casserole that you can prep in 10 minutes and that makes 6 hearty portions.

My High Protein Breakfast Casserole is one of my favorite starts to my morning. It is so delicious and incredibly easy to make. Packed with sausage, savory veggies and loads of protein rich eggs; I’m always grateful to have a batch of this recipe for busy mornings.

Whether you’re feeding a family like me, prepping for the week or hosting brunch, this casserole is comforting and made with simple, wholesome ingredients. Just bake, slice and enjoy a nourishing breakfast whenever you need it. For more simple and yummy breakfasts, try this Easy, Cheesy, Oven Baked Breakfast Taquitos, my Broccoli Cheddar Quiche or my Everything Avocado Toast.

WHY YOU’LL LOVE THIS RECIPE

I love this high protein breakfast casserole because it’s the perfect combination of filling, healthy and convenient. It’s packed with protein and veggies, so I feel satisfied and energized all morning without having to spend a lot of time in the kitchen. It’s also quick to prepare so I can easily add it to a meal prep roster. 

I also love how versatile high protein breakfast casseroles are. I can change up the veggies, cheese or seasonings depending on what I have on hand. Plus, it reheats beautifully, making it a go-to for busy mornings or meal prep days.

INGREDIENTS

• Eggs: These build a high protein base in my high protein breakfast casserole.
• Cottage cheese: Adds extra protein and makes the bake fluffy and tender.
• Milk or unsweetened almond milk: Loosens the mixture in high protein breakfast casseroles and creates a smooth, custardy texture.
• Garlic powder: Much easier than flavoring with fresh garlic cloves.

• Your choice of meat: I’ll play around with using pork, turkey or chicken sausage that have been cooked and crumbled.
• Bell peppers: I love the crunch and color these add.
• Onion: You can also use leeks instead.
• Baby spinach or kale: I add in greens that wilt easily into the bake.
• Mushrooms: These add umami and moisture as they cook down in the protein casserole.
• Shredded cheddar or mozzarella cheese: Choose a cheese that melts in for richness, creaminess and extra protein.

Check out the recipe card below for the full ingredient and quantity list.

HOW TO MAKE THIS RECIPE

Prepare the oven and pan: Preheat the oven to 375F and lightly coat a 9×13 inch baking dish with cooking spray.

Cook the filling ingredients: Cook the sausage in a skillet over medium heat until browned. Add the peppers, mushrooms, and onions, sauteing for 3 to 4 minutes until they soften. Stir in the spinach just until it wilts, then remove from heat and squeeze out any extra moisture from the veggies.

Make the savory custard: In a large bowl, whisk together the eggs, cottage cheese, milk, salt, pepper and garlic powder until well combined.

Build the high protein breakfast casserole: Spread the sausage and vegetables evenly in the prepared baking dish. Pour the egg mixture over top. Add half of the shredded cheese, gently stir to combine, then sprinkle the remaining cheese on top.

Bake: Bake the protein casserole uncovered for 30 to 35 minutes, or until the center is set and the edges are lightly golden. Allow it to cool slightly before slicing.

Portion: Cut your high protein breakfast casserole into squares and enjoy warm, at room temperature, or reheated throughout the week.

SUBSTITUTIONS AND VARIATIONS

For ingredient swaps, here are a few I make often:

Sausage: Swap with ground turkey, chicken, lean beef, diced ham or crumbled tofu for a meatless version of this high protein breakfast casserole.

Cottage cheese: Use ricotta, Greek yogurt or a dairy free cottage cheese alternative.

Milk: Replace with any unsweetened non dairy milk (almond, oat, cashew, soy) or regular milk.

Cheese: Cheddar, mozzarella, pepper jack, feta or your favorite dairy free shredded cheese all work in high protein breakfast casseroles.

Seasonings: Replace garlic powder with onion powder, Italian seasoning, smoked paprika or your preferred spice blend.

Want to add more veggies? Try broccoli, zucchini, kale or extra mushrooms for a veggie-loaded bake.

Craving a Southwest version? Add black beans, corn, chili powder and top with pepper jack. SO GOOD!

Love Mediterranean flavors? Mix in sun dried tomatoes, olives, oregano and crumble feta on top.

Want to boost the protein? Add turkey bacon, cooked chicken breast or a couple extra eggs.

STORAGE AND MAKE AHEAD

I store leftover high protein breakfast casserole in an airtight container in the fridge for 3 to 4 days. Reheat slices in the microwave or oven until warmed through. 

For longer storage, freeze portions tightly wrapped or in freezer safe containers for up to 2 to 3 months. Thaw overnight in the fridge before reheating.

SERVING AND PAIRING

I love to serve a slice or wedge of high protein breakfast casserole warm with a side of fresh fruit or a simple green salad. It might seem odd to eat salad in the morning but it’s a great way to get in some fiber, early in the day.

I’ll sometimes pair it with salsa, hot sauce or a dollop of Greek yogurt. It also works tucked into a gluten free wrap for an easy breakfast on the go. For a brunch spread, I love it alongside roasted potatoes, avocado slices or a light smoothie.

TIPS AND PROBLEM SOLVING

• Whenever I make high protein breakfast casseroles, I squeeze excess moisture from the cooked veggies to prevent a watery bake.
• Let the casserole rest for 5 to 10 minutes after baking so it slices cleanly.
• If you prefer a fluffier texture, whisk the eggs for an extra minute to incorporate more air.
• Add the cheese in two layers; mixed in and on top, for the best melt and flavor.
• Chop the veggies small and evenly so they cook quickly and distribute well throughout the high protein breakfast casserole.

FREQUENTLY ASKED QUESTIONS

OTHER BREAKFAST RECIPES TO TRY

Freezer Friendly Egg, Bacon and Cheese Breakfast Sandwiches

Freezer Friendly Breakfast Burritos

Banana Cream Pie Overnight Oats

Loaded Hash Browns

French Onion Frittata

High Protein Breakfast Casserole

Taylor Jackzen

This High Protein Breakfast Casserole is a great way to pack in your protein at the start of your day. Brimming with eggs, sausage, and veggies, it's a hearty, make-ahead breakfast that is perfect for bus mornings or meal prep.

5 from 1 vote

Print Recipe Pin Recipe

Prep Time 10 minutes mins

Cook Time 35 minutes mins

Total Time 45 minutes mins

Course Breakfast

Servings 6

Ingredients

  

For the Base

• 10 large eggs
• 1 cup cottage cheese
• ½ cup milk or unsweetened almond milk
• 1 tsp salt
• ½ tsp black pepper
• ½ tsp garlic powder

Protein + Veggies

• 1 lb pork sausage, turkey sausage, or chicken sausage cooked and crumbled
• 1 cup bell peppers chopped
• ½ cup onion chopped
• 1 cup baby spinach or kale roughly chopped
• 1 cup mushrooms sliced
• 1 cup shredded cheddar or mozzarella cheese or a mix

Instructions

 

• Preheat oven to 375°F. Lightly spray a 9×13-inch baking dish with cooking spray.
• In a skillet over medium heat, cook sausage until browned. Add peppers, mushrooms, and onions; sauté 3–4 minutes until softened. Stir in spinach just until wilted. Remove from heat and squeeze out moisture from vegetables.
• In a large bowl, whisk together eggs, cottage cheese, milk, salt, pepper, and garlic powder until smooth.
• Add the sausage-veggie mixture to the prepared baking dish. Pour egg mixture evenly over top. Sprinkle with half of the shredded cheese and mix then top with remaining cheese.
• Bake uncovered for 30–35 minutes, until the center is set and the edges are golden. Let cool slightly before slicing.
• Cut into squares and enjoy! Great warm, room-temp, or reheated throughout the week.