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Baked breakfast casserole in a white dish, topped with melted cheese, mushrooms, broccoli, and red peppers, with fresh ingredients in the background

Easy High-Protein Breakfast Casserole for Busy Mornings

This Easy High-Protein Breakfast Casserole is your new go-to for busy mornings. Packed with lean turkey sausage, eggs, veggies, and cheese, it’s a hearty, satisfying meal that fuels your day with 29 grams of protein per serving. Best of all, it’s perfect for meal prep—just bake once and enjoy grab-and-go slices all week.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 40 minutes
Total Time 55 minutes
Servings: 6
Course: Breakfast
Cuisine: American
Calories: 280
Ingredients Equipment Method Video Notes

Ingredients
  

  • 1 lb (450g) lean turkey sausage or chicken sausage
  • 8 large eggs
  • 1 cup (240 ml) egg whites
  • 1 cup (120 g) shredded reduced-fat cheddar cheese
  • 1 cup (120 g) diced bell peppers mixed colors
  • 1 small onion diced
  • 2 cups (60 g) fresh spinach roughly chopped
  • 1 cup (240 ml)  milk  skim or unsweetened almond milk
  • ½ tsp garlic powder
  • ½ tsp paprika
  • ½ tsp black pepper
  • ½ tsp salt  optional, adjust to taste
  • Cooking spray or 1 tsp olive oil

Equipment

  • 9x13-inch baking dish or 8×8 for a thicker casserole
  • Large skillet
  • Mixing bowls
  • Whisk
  • Cutting board and knife
  • Measuring cups and spoons

Method
 

  1. Preheat Oven: Set your oven to 375°F (190°C). Grease a 9×13-inch baking dish with cooking spray or olive oil.
    Cook the Sausage: In a skillet over medium heat, cook the turkey sausage until browned, breaking it apart with a spatula. Drain excess fat if needed.
    Sliced sausage pieces being cooked in a skillet with onions and herbs, stirred with a wooden spatula
  2. Sauté Veggies: Add diced onion and bell peppers to the skillet. Cook for 4–5 minutes until softened. Stir in spinach and cook until just wilted. Remove from heat.
    Whisk Eggs: In a large mixing bowl, whisk together eggs, egg whites, milk, garlic powder, paprika, salt, and black pepper.
    A mixing bowl with whisked eggs, milk, and seasonings being combined with a wire whisk
  3. Assemble Casserole: Spread the cooked sausage and veggies evenly in the baking dish. Pour the egg mixture over the top, then sprinkle with shredded cheddar cheese.
    Bake: Place in the preheated oven and bake for 35–40 minutes, or until the center is set and a knife inserted comes out clean.
    A glass baking dish filled with uncooked breakfast casserole layers of sausage, broccoli, red peppers, and shredded cheese
  4. Cool & Serve: Let it cool for 5–10 minutes before slicing into 6 portions. Serve warm or refrigerate for up to 5 days.
    A close-up of a slice of baked breakfast casserole with sausage, eggs, cheese, peppers, and herbs on top, ready to serve

Video

Notes

Nutrient Amount per Serving (~220g)
Calories 280
Carbohydrates 6 g
Protein 29 g
Fat 14 g
Saturated Fat 5 g
Polyunsaturated Fat 2 g
Monounsaturated Fat 4 g
Trans Fat 0 g
Cholesterol 260 mg
Sodium 620 mg
Potassium 480 mg
Fiber 1 g
Sugar 3 g
Vitamin A 2100 IU (42% DV)
Vitamin C 35% DV
Calcium 180 mg (18% DV)
Iron 2.5 mg (14% DV)

Cooking Tips

  • Swap in Greek yogurt in place of some milk for extra creaminess and protein.
  • Use different veggies like zucchini, mushrooms, or broccoli to switch things up.
  • Make it spicy by adding jalapeños or a dash of hot sauce.
  • For a meal-prep boost, cut into squares and wrap individually for quick reheating.