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A close-up of a hearty breakfast casserole slice with a runny egg, melted cheese, sausage, and veggies on a plate.

Easy Cheesy Sausage & Egg Breakfast Casserole

This hearty and incredibly easy breakfast casserole is packed with savory breakfast sausage, fluffy eggs, crusty bread, and melted cheese, making it perfect for feeding a crowd or for stress-free meal prep.
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Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Servings: 8 servings
Course: Breakfast, Brunch, Main Course
Cuisine: American
Calories: 450
Ingredients Equipment Method Notes

Ingredients
  

For the Casserole
  • 6-8 slices day-old bread crusty white bread or sourdough, cubed into 1-inch pieces
  • 1 lb ground breakfast sausage mild or spicy, cooked and drained
  • 1/2 medium yellow onion diced
  • 1/2 medium bell pepper any color, diced
  • 2 cups shredded sharp cheddar cheese or Monterey Jack, divided
  • 10 large eggs
  • 1.5 cups milk whole milk recommended
  • 1/2 tsp salt
  • 1/4 tsp black pepper
  • 1/2 tsp dry mustard powder optional, enhances savory flavor
  • 1 tbsp olive oil if needed for cooking vegetables

Equipment

  • 9x13 inch baking dish
  • Large Skillet
  • Large Mixing Bowl
  • Whisk

Method
 

Prepare Ingredients
  1. Preheat your oven to 350°F (175°C). Lightly grease a 9x13 inch baking dish with non-stick cooking spray or butter.
  2. Distribute the cubed bread evenly across the bottom of the prepared baking dish.
  3. In a large skillet over medium-high heat, cook the ground breakfast sausage, breaking it up with a spoon, until it is fully browned. Drain off any excess grease and set the sausage aside.
  4. If the skillet is dry, add 1 tbsp olive oil. Add the diced onion and bell pepper to the skillet and sauté for 5-7 minutes, until softened. Add the cooked sausage back to the skillet and stir to combine.
Assemble Casserole
  1. Sprinkle the cooked sausage and vegetable mixture evenly over the bread cubes in the baking dish. Top with 1.5 cups of the shredded cheese.
  2. In a large mixing bowl, whisk together the eggs, milk, salt, black pepper, and dry mustard powder (if using) until well combined.
  3. Carefully pour the egg mixture evenly over the sausage, vegetables, and bread in the baking dish, ensuring the bread is mostly submerged.
  4. Gently press down on the bread with a spatula to help it absorb the egg mixture. Let the casserole sit for 10-15 minutes on the counter to allow the bread to soak up the liquid. (For a make-ahead option, cover and refrigerate overnight at this point.)
Bake and Serve
  1. Bake the casserole in the preheated oven for 30 minutes. Remove from the oven, sprinkle the remaining 1/2 cup of shredded cheese over the top, and return to the oven for another 15-20 minutes, or until the casserole is set, golden brown, and the cheese is bubbly.
  2. Let the casserole rest for 5-10 minutes before slicing and serving. This allows it to set completely and makes for cleaner slices.

Notes

For a make-ahead option, assemble the casserole the night before (after step 9). Cover tightly with plastic wrap and refrigerate. In the morning, remove from the fridge 30 minutes before baking and bake as directed, adding an extra 5-10 minutes to the initial baking time if it's still very cold.
Feel free to customize with other vegetables like mushrooms, spinach (sautéed and squeezed dry), or different cheeses like Gruyère or Colby Jack.