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If you’re looking for a lighter, low calorie, high-protein breakfast that still delivers big flavor, this Veggie and Egg White Casserole is the perfect choice.
It’s loaded with fresh spinach, sautéed mushrooms, sweet bell peppers, and tangy feta, all baked into a fluffy egg white base.
Not only is it low in calories and high in protein, but it’s also a great make-ahead meal that you can bake once and enjoy all week. Whether you’re meal prepping, sticking to a low-calorie, low-carb diet, or just love a fresh and flavorful breakfast, this casserole is a winner.

Why You’ll Love This Veggie Breakfast Casserole
- A low-calorie, high-protein breakfast that keeps you full
- Perfect for meal prep—just reheat and eat all week
- Packed with nutrient-dense vegetables for a healthy start to the day
- Easily customizable—swap in your favorite veggies and cheeses
Ingredients
- 2 cups fresh spinach, chopped
- 1 cup mushrooms, sliced
- 1 small bell pepper, diced (red, yellow, or green)
- ½ small onion, diced
- 2 garlic cloves, minced
- 12 large egg whites
- ½ cup unsweetened almond milk (or regular milk)
- ½ teaspoon salt
- ¼ teaspoon black pepper
- ¼ teaspoon crushed red pepper flakes (optional)
- ½ teaspoon dried oregano
- ½ teaspoon garlic powder
- ½ cup crumbled feta cheese
- 1 tablespoon olive oil (for sautéing)
Instructions
Preheat the oven to 375°F and grease a 9×13-inch baking dish with cooking spray.
Heat olive oil in a large skillet over medium heat. Add onions and garlic and sauté until fragrant, about 2 minutes.
Add mushrooms and bell peppers, cooking for another 3-4 minutes until softened. Stir in chopped spinach and cook until wilted. Remove from heat.
In a large bowl, whisk together the egg whites, milk, salt, pepper, oregano, garlic powder, and red pepper flakes.
Spread the sautéed veggies evenly in the greased baking dish. Sprinkle crumbled feta on top.
Pour the egg white mixture over the vegetables, making sure everything is evenly distributed.
Bake uncovered for 30-35 minutes, or until the casserole is set and lightly golden on top.
Let cool for a few minutes before slicing. Serve warm or store in the fridge for meal prep.
Nutrition Information (Per Serving, based on 6 servings)
Calories: 120
Protein: 15g
Carbs: 5g
Fat: 4g
Tips for the Best Veggie & Egg White Casserole
- Use liquid egg whites if you want to skip the hassle of separating eggs
- For an even creamier texture, add ½ cup of cottage cheese to the egg mixture before baking
- Swap feta for goat cheese or shredded mozzarella for a different flavor twist
- Add extra protein by tossing in diced turkey or chicken sausage
Conclusion
This Veggie-Packed Egg White Casserole proves that a healthy, protein-packed breakfast can still be delicious and satisfying. Whether you’re looking for an easy meal prep option, a low-calorie breakfast, or a way to start your day with more veggies, this dish checks all the boxes.
Prep it once, enjoy it all week, and fuel your mornings with fresh, wholesome goodness—because eating healthy should always taste this good.

Please note: This website contains affiliate links. As an Amazon Associate, we earn from qualifying purchases at no additional cost to you.
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