High-Protein Breakfast Casserole

This high protein breakfast casserole is the perfect way to kick off your morning with a hearty, flavorful meal. It’s loaded with eggs, cottage cheese, and a medley of fresh vegetables that bring color and texture. The cottage cheese isn’t just for protein—it adds a creamy, dreamy texture without overpowering the dish. Sautéed mushrooms, sweet bell pepper, and tender kale round out every bite with wholesome flavor and nutrients. You can enjoy this casserole warm right out of the oven, or slice and reheat it during busy mornings to keep breakfast delicious and stress-free all week long.

Megan Ginsberg is the Senior Editor at EatingWell, known for her sharp eye for detail and her passion for discovering new recipes to share. With over 20 years focused on food-related editing, she truly understands how a well-planned meal brings comfort and joy to the table.

Emily Lachtrupp is a registered dietitian with a wealth of experience in nutrition counseling, meal planning, and recipe breakdowns. She works closely with clients managing everything from diabetes to digestive health, and loves embracing Vermont’s great outdoors with her family and dog, Winston, whenever she can.

• Adding cottage cheese to the eggs creates a rich and creamy custard-like base while boosting the protein for extra staying power. 
• This casserole is perfect to make ahead, so you can enjoy stress-free, protein-packed breakfasts all week long. 
• Feel free to customize the veggies to suit your family’s tastes or whatever you have in the fridge.

This high protein breakfast casserole is a delicious, practical way to fuel your mornings with a blend of eggs, creamy cottage cheese, and fresh veggies. The cottage cheese blends into the eggs for a smooth and luscious texture while adding a large protein punch. Baked until golden brown and beautifully set, this casserole is great for serving a hungry family or meal prepping for the week ahead. We love the mix of antioxidant-rich veggies here, but it’s super flexible: swap in whatever veggies your family prefers! Keep reading for expert tips on how to know when it’s perfectly cooked, plus easy ingredient swaps and storage ideas for this kitchen favorite. 

This high protein breakfast casserole makes mornings easier with its simple, make-ahead preparation. Eggs and cottage cheese combine to create a creamy, custard-like base that’s studded with earthy mushrooms, crisp bell pepper, and tender wilted kale. It’s filling enough to feed a crowd yet portion-friendly for breakfasts throughout your busy week.

You’ll get about 6 servings from this recipe, with about 25 minutes of hands-on prep time and a little patience during baking (see details above). Cottage cheese adds not only protein but also richness, while cooking the veggies first keeps everything perfectly set and not watery.

• Here’s what you’ll find below: a full list of ingredients, clear step-by-step instructions, make-ahead and reheating tips, pro advice from our test kitchen, plus flavor twists and storage tips to keep things fresh.
• This recipe is perfect for anyone chasing a filling, protein-rich breakfast that’s simple, family-friendly, and ready to prep ahead.

Protein, Texture, and Convenience

This casserole ticks all the right boxes: it’s packed with protein, loaded with veggies, easy to prepare ahead, and endlessly tweakable. Whether you’re after creamy, custard-like slices to savor slowly or grab-and-go portions to fuel busy mornings, this dish delivers great taste, texture, and nutrition each time.

• Dreamy, custard-like texture: Blending eggs with creamy cottage cheese results in a smooth, tender casserole with a nicely golden top—no dry, rubbery egg bits here.
• A real protein powerhouse: Eggs plus half a cup of cottage cheese add around 12 grams of protein, helping keep you full, energized, and ready to take on your day.
• Veggie-packed and nutrient-rich: Sauteed mushrooms, bell pepper, and kale add fiber, antioxidants, and vital nutrients. Mushrooms help feed your gut’s good bacteria, kale is bursting with vitamin C, and eggs offer choline to support brain and nervous system health.
• Perfect for meal prep: Six servings means you can bake it once then enjoy quick, nutritious breakfasts all week, storing leftovers in the fridge or freezer and reheating with ease whenever you need.
• Totally adaptable: Swap out cheeses, use Greek yogurt or silken tofu instead of cottage cheese, add protein-rich extras like cooked sausage or beans, or bake in muffin tins for convenient single servings. This recipe adjusts to your kitchen and tastes.
• Reliable, foolproof results: Our test kitchen tips like precooking veggies, layering them right, and checking for an internal temperature of 165°F guarantee a casserole that’s not watery and perfectly golden every time.

In a nutshell, this high protein breakfast casserole is an easy, tasty, and versatile way to start busy mornings, suited for everything from weekday meal prep to weekend brunches.

• Eggs bring protein, plus choline, which is essential for memory, mood, and nervous system support. 
• Cottage cheese packs a protein punch—half a cup adds about 12 grams—fueling your muscles and digestive health. It also provides calcium and phosphorus for strong bones. 
• Mushrooms serve as prebiotic powerhouses, feeding the good bacteria in your gut and supporting overall wellness. They’re great for heart health, helping regulate blood pressure and blood sugar. 
• Kale delivers antioxidants that protect against certain cancers and supplies Vitamin C, which supports your immune system and keeps you feeling your best.

Essential Ingredients

• 2 tablespoons extra-virgin olive oil, divided
• 4 ounces sliced fresh wild mushrooms, such as oyster or shiitake (about 1 cup)
• 1 medium red bell pepper, chopped (about 1¼ cups)
• 1 small yellow onion, chopped (about 1 cup)
• ¼ teaspoon salt, divided
• 1 (5-ounce) package baby kale
• 1½ teaspoons garlic powder
• ¼ teaspoon crushed red pepper
• 8 large eggs
• ½ cup small-curd 2% reduced-fat cottage cheese
• ⅓ cup whole milk
• 1½ cups shredded Colby-Jack cheese, divided

Assemble and Bake

1. Preheat oven to 350°F and lightly grease an 8-inch square baking dish with cooking spray.
2. Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
3. Add sliced mushrooms and cook undisturbed about 4 minutes until they start to brown.
4. Stir mushrooms and continue cooking, stirring occasionally, until their moisture evaporates, about 3 more minutes.
5. Add chopped red bell pepper, chopped yellow onion, 1/8 teaspoon salt and the remaining 1 tablespoon olive oil; cook, stirring often, until softened, about 4 minutes.
6. Add baby kale, 1½ teaspoons garlic powder and ¼ teaspoon crushed red pepper; cook, stirring, until the kale wilts, about 2 minutes.
7. Remove the skillet from heat and let the vegetable mixture cool about 5 minutes.
8. In a blender combine 8 large eggs, ½ cup small-curd cottage cheese, 1/3 cup whole milk, 3/4 cup shredded Colby-Jack and 1/8 teaspoon salt; blend on low until smooth, about 20 seconds.
9. Spread half of the cooled vegetable mixture evenly in the prepared baking dish; pour the egg-and-cheese mixture over the veggies and scatter the remaining vegetable mixture on top.
10. Sprinkle the remaining 3/4 cup shredded Colby-Jack over the casserole.

11. Bake until the edges are puffed and golden brown, about 40 minutes.

    

12. Let the casserole rest at least 10 minutes before slicing.

Tips for a Perfect Casserole

These are the essential tips we picked up while testing this recipe to make sure your high protein breakfast casserole turns out perfectly every time! 

• Layering the veggies in two parts helps them distribute evenly throughout the casserole. Don’t stress if the top layer sinks into the eggs — it creates a wonderful texture contrast inside.
• Cooking the veggies first not only brings out their flavor but also reduces moisture so the casserole bakes up firm, not watery. Mushrooms release the most water, so start with those.
• Look for golden, puffed edges and a set center when it’s done—cues we also highlight in our High Protein Creamy Chicken Noodle Casserole. A gentle jiggle of the pan can help check doneness, or use an instant-read thermometer. Eggs are safe and fully cooked at 165°F.

Easy Swaps and Add-Ins

Mix it up with these simple swaps that let you customize your high protein breakfast casserole to your tastes or pantry supplies:

• Cheese: Swap the Colby-Jack for sharp cheddar, Monterey Jack, spicy Pepper Jack, or tangy feta. Just keep the total cheese amount the same.
• Cottage cheese alternatives: For a similar creamy texture, plain Greek yogurt works great. To keep it dairy-free or plant-based, blend silken tofu or use plain unsweetened plant-based yogurt—the texture will be a bit different but still tasty.
• Veggies: Substitute spinach for kale or use cooked broccoli, shredded Brussels sprouts, zucchini, or asparagus. Just be sure to cook and drain any high-moisture veggies first to avoid watery casserole.
• Extra protein: Mix in cooked, crumbled turkey sausage, diced ham, or bacon before baking. Vegetarians can add white beans or a bit of cooked quinoa for a protein boost.
• Different formats: Bake this in a greased muffin tin for handy single-serve portions. Bake for 18–22 minutes until set. For another grab-and-go breakfast, try the 5 Minute Protein Breakfast Sandwich. For a heartier dish, layer cooked diced potatoes or frozen hash browns on the bottom before adding the egg mixture.
• Flavor enhancers: Add fresh herbs like chives, parsley, or dill. Swap garlic powder for minced fresh garlic. Spice it up with smoked paprika or extra red pepper flakes.

Storing, Freezing, and Reheating

Keep your casserole fresh and tasty with these storage and prep pointers, designed to save you time and reduce waste:

• Refrigerate: Let the casserole cool to room temperature (no more than 2 hours), then cover tightly or transfer to an airtight container. Store in the fridge for up to 3 days.
• Make-ahead (unbaked): Assemble the casserole in your baking dish, cover it well, and keep it refrigerated for up to 24 hours before baking. If you bake it straight from the fridge, add 5–10 minutes to cook time and bake until the center reaches 165°F. For another prep-friendly breakfast idea, try Vegan Breakfast Bowls.
• Freeze: Slice the casserole, wrap individual pieces tightly in plastic wrap and foil or use freezer containers. Freeze for up to 2 months. Thaw overnight in the fridge before reheating. For frozen reheating, increase cook time and check for an internal temp of 165°F.

• Reheat methods:

  • Oven: Preheat to 325–350°F, place slices in a baking dish, cover with foil, and warm for 10–20 minutes from chilled, longer if frozen.
  • Microwave: Heat slices in short bursts (15–30 seconds), turning between intervals to avoid tough, rubbery eggs.
  • Air fryer: Reheat at 325–350°F for 5–8 minutes to get crispy edges but watch carefully to keep it from drying out.
• Food safety note: Don’t leave your casserole out longer than 2 hours at room temperature. Always reheat until the center hits 165°F before eating.

Answers to Common Questions

• What other vegetables can I use?

  This casserole is super flexible—any veggie works as long as you cook it first to reduce moisture. Spinach works well instead of kale. Try steamed broccoli or shredded Brussels sprouts for a tasty twist.

• What’s the best way to reheat this high-protein breakfast casserole?

  The microwave is great for a quick warm-up, just heat in short intervals of 15 to 20 seconds. This keeps the eggs from becoming overcooked and rubbery.

• Do I have to use a blender?

  Using a blender creates a silky smooth egg and cottage cheese mixture which really lifts the texture. You can whisk everything by hand if needed, but expect a slightly chunkier, less creamy consistency.