Start the week with six filling breakfasts already prepared. This High-Protein Breakfast Casserole layers roasted potatoes, lean turkey sausage, colorful peppers, whole eggs, egg whites and melted cheddar into one easy make-ahead meal.
Why You’ll Love This Breakfast Casserole
- Approximately 40–48 grams of protein per serving
- Six complete make-ahead breakfasts
- Eggs, sausage, potatoes, vegetables and cheese in one dish
- Easy to refrigerate or freeze in individual portions
- Simple to customize with different vegetables and seasonings
Ingredients
Makes 6 servings
Potatoes
- 1½ pounds Yukon Gold or russet potatoes, cut into ½-inch cubes
- 1 tablespoon olive oil
- 1 teaspoon garlic powder
- 1 teaspoon smoked paprika
- ½ teaspoon onion powder
- ½ teaspoon salt
- ¼ teaspoon black pepper
Turkey Sausage and Vegetables
- 1½ pounds lean turkey breakfast sausage
- 1 red bell pepper, diced
- 1 green bell pepper, diced
- 1 small yellow onion, diced
- 2 garlic cloves, minced
- Cooking spray, as needed
Egg Mixture
- 12 large eggs
- 2 cups liquid egg whites
- ½ cup milk of choice
- ½ teaspoon salt
- ½ teaspoon black pepper
- ½ teaspoon garlic powder
- 1½ cups shredded reduced-fat cheddar or Mexican-blend cheese, divided
- Optional sliced green onions, salsa or hot sauce for serving
Step-by-Step Instructions
1. Roast the Potatoes
Preheat the oven to 425°F. Toss the potatoes with olive oil, garlic powder, smoked paprika, onion powder, salt and pepper. Spread them on a large sheet pan and roast for 22–30 minutes, turning halfway, until browned and nearly tender.
2. Cook the Turkey Sausage
While the potatoes roast, heat a large nonstick skillet over medium heat. Add the turkey sausage and cook for 7–10 minutes, breaking it into small crumbles, until browned and fully cooked to 165°F. Transfer it to a plate.
3. Sauté the Vegetables
Coat the skillet lightly with cooking spray if needed. Add the red pepper, green pepper and onion. Cook for 5–7 minutes until softened. Add the minced garlic and cook for another 30 seconds.
4. Prepare the Egg Mixture
Reduce the oven temperature to 375°F. In a large bowl, whisk the whole eggs, egg whites, milk, salt, pepper and garlic powder until fully combined.
5. Assemble the Casserole
Coat a 9-by-13-inch baking dish with cooking spray. Spread the roasted potatoes evenly across the bottom. Add the turkey sausage and sautéed vegetables. Sprinkle one cup of cheese over the filling, pour the egg mixture evenly into the dish and finish with the remaining cheese.
6. Bake and Portion
Bake uncovered for 35–45 minutes, until the center is set and reaches 160°F. Rest for 10–15 minutes before cutting the casserole into six equal portions. Cool before placing the portions in meal-prep containers.
Estimated Nutrition
Per serving, based on 6 servings: approximately 500–620 calories, 40–48 grams of protein, 35–48 grams of carbohydrates and 22–31 grams of fat.
Nutrition values are estimates and will vary according to the turkey sausage, potatoes, eggs, milk, cheese, cooking oil, toppings and exact portions used.
Meal-Prep and Storage Tips
- Refrigerator: Cool promptly and store in airtight containers for up to 3–4 days.
- Microwave: Cover loosely and heat in 45-second intervals until the center reaches 165°F.
- Oven: Cover with foil and reheat at 350°F until hot throughout.
- Freezer: Wrap cooled individual portions tightly and freeze for up to 2 months.
- Thawing: Thaw frozen portions overnight in the refrigerator before reheating for the best texture.
- Cold toppings: Keep salsa, avocado, Greek yogurt and green onions separate until serving.
Easy Swaps and Variations
- Replace turkey sausage with chicken sausage or seasoned lean ground turkey.
- Use sweet potatoes instead of Yukon Gold or russet potatoes.
- Add spinach, mushrooms, jalapeños, broccoli or zucchini.
- Replace cheddar with pepper jack, mozzarella, feta or a reduced-fat Mexican blend.
- Use additional egg whites and fewer whole eggs to reduce the fat.
- Add taco seasoning and serve with salsa for a Southwest version.
- Skip the potatoes and add more vegetables for a lower-carbohydrate option.
Food-Safety Note
Cook turkey sausage to a minimum internal temperature of 165°F and the egg casserole to 160°F. Refrigerate prepared food within two hours, keep it at 40°F or below and reheat leftovers to 165°F.
Frequently Asked Questions
Can I assemble the casserole the night before?
Yes. Cook and cool the potatoes, sausage and vegetables, assemble the casserole, cover it and refrigerate overnight. Bake it directly from the refrigerator, allowing several additional minutes as needed.
How do I know when the casserole is finished?
The center should be set rather than wet or jiggly, and a food thermometer inserted near the center should read at least 160°F.
Why is my breakfast casserole watery?
Vegetables with substantial moisture can release water while baking. Sauté the vegetables first, avoid overcrowding the dish and let the casserole rest before slicing.
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CIWO Meal-Prep Notes
High-Protein Breakfast Casserole works best when the serving size is planned around your own calorie, protein and training needs. Nutrition numbers in recipes are estimates because brands, ingredient weights, sauces and substitutions can change the final totals.
Storage, reheating and food safety
Cool cooked food appropriately, portion it into clean covered containers and refrigerate promptly. As a practical rule, many cooked leftovers are best used within about three to four refrigerated days; freeze later-week portions when appropriate. Reheat hot components thoroughly, and keep fresh toppings or cold sauces separate when that improves texture.
Adjust the meal for your goal
For a higher-energy training meal, increase an appropriate carbohydrate portion or add a nutrient-dense side. For a lighter meal, emphasize vegetables and moderate calorie-dense sauces, oils and cheese. For more protein, adjust the main lean-protein portion or pair the meal with a protein-rich side.
Make the nutrition estimate more accurate
Weigh or measure the ingredients you actually use and calculate the batch from their labels, then divide by the number of portions. This is more reliable than assuming every version of the recipe has identical calories or macros.
Explore more CIWO meal-prep recipes or pair your nutrition plan with the CIWO workout library.