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Slice of savory breakfast casserole with sausage, eggs, vegetables, and melted cheddar cheese served on a plate.

Savory Make-Ahead Breakfast Casserole

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Prep Time 20 minutes
Cook Time 45 minutes
Chill Time 30 minutes
Total Time 1 hour 35 minutes
Servings: 12
Course: Breakfast / Brunch
Cuisine: American
Calories:
Ingredients Method Notes

Ingredients
  

  • Base
  • 4 cups crusty bread, cubed
  • 1 teaspoon olive oil
  • Filling
  • 1 pound ground pork sausage
  • ¾ cup chopped yellow onion
  • 2 garlic cloves, minced
  • 2 cups chopped bell peppers
  • 1 cup sliced mushrooms
  • 1 cup chopped fresh spinach
  • Egg Mixture
  • 12 large eggs
  • ¼ teaspoon salt
  • ⅛ teaspoon black pepper
  • ⅔ cup milk or half-and-half
  • 1 cup shredded cheddar cheese
  • Optional garnish: chopped green onion or parsley

Method
 

  1. Before You Begin
  2. Preheat and prepare your cookware as needed. Cooking times and results may vary depending on your equipment and ingredients.
  3. Prepare the Pan
  4. Lightly grease a 9×13-inch baking dish. Spread cubed bread evenly across the bottom. If using very fresh bread, lightly toast before assembling to improve absorption.
  5. Cook the Sausage and Vegetables
  6. Heat olive oil in a skillet over medium heat. Add sausage and cook until browned and no longer pink. The internal temperature should reach 160°F (71°C).
  7. Add onion, garlic, bell peppers, mushrooms, and spinach. Cook until vegetables are softened. Remove from heat.
  8. Mix the Egg Mixture
  9. In a large bowl, whisk eggs, salt, pepper, milk, and shredded cheddar cheese until fully combined and evenly mixed.
  10. Assemble
  11. Spread the sausage and vegetable mixture evenly over the bread. Pour egg mixture on top. Gently press bread down to help it absorb the liquid.
  12. Chill
  13. Cover and refrigerate for at least 30 minutes or up to 24 hours. This step ensures even texture and clean slicing.
  14. Bake
  15. Preheat oven to 375°F (191°C).
  16. Let casserole sit at room temperature for 10–15 minutes.
  17. Bake uncovered for 40–45 minutes, until the top is lightly golden and the center is fully set with no visible liquid egg remaining. For food safety, verify that the internal temperature reaches 160°F (71°C) before removing from the oven.
  18. Rest and Serve
  19. Allow casserole to rest 5–10 minutes before slicing. This helps it firm up for clean slices. Serve warm.

Notes

  • Cook sausage to 160°F (71°C).
  • Bake casserole to 160°F (71°C).
  • Reheat leftovers to 165°F (74°C).
  • Do not leave at room temperature for extended periods.
  • Discard if odor, texture, or appearance changes.
  • Refrigerate leftovers within 2 hours in an airtight container for up to 4–5 days.