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A hearty overnight breakfast casserole with eggs, cheese, and vegetables.

Classic Overnight Breakfast Casserole with Eggs

Prepare this delicious breakfast casserole the night before for an easy and satisfying meal the next morning. It features bread, sausage (or bacon), cheese, and a flavorful egg mixture.
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Prep Time 20 minutes
Cook Time 1 hour
Total Time 1 hour 20 minutes
Servings: 8 people
Calories: 450
Ingredients Equipment Method Notes

Ingredients
  

Main Ingredients
  • 1 loaf day-old bread (challah, brioche, or sourdough) around 1 pound, cut into 1-inch cubes
  • 1 pound breakfast sausage or bacon cooked and crumbled
  • 1.5 cups shredded cheddar cheese
  • 1 onion small, finely chopped
  • 1 red bell pepper finely diced
  • 12 large eggs
  • 2 cups whole milk
Seasonings & Other
  • 1 teaspoon Dijon mustard optional
  • 0.5 teaspoon salt
  • 0.25 teaspoon black pepper
  • red pepper flakes pinch, optional
  • butter or cooking spray for greasing the baking dish

Equipment

  • 9x13-inch baking dish
  • large bowl
  • whisk
  • plastic wrap

Method
 

Preparation
  1. Lightly grease a 9x13-inch baking dish, then spread the bread cubes evenly over the bottom.
  2. Sprinkle the cooked sausage or bacon, chopped onion, and diced red bell pepper over the bread cubes, and top with shredded cheese.
Assemble & Chill
  1. In a large bowl, whisk together eggs, milk, Dijon mustard (if using), salt, pepper, and red pepper flakes (if using) until well combined.
  2. Pour the egg mixture over the layers in the baking dish, cover tightly with plastic wrap, and refrigerate for at least 4 hours or overnight.
Bake & Serve
  1. Preheat oven to 375°F (190°C), then remove the casserole from the refrigerator and let it sit for 20-30 minutes.
  2. Remove plastic wrap and bake for 45-60 minutes until puffed, golden, and set in the center.
  3. Let the casserole rest for 5-10 minutes before slicing and serving for best results.

Notes

For best results, allow the casserole to chill overnight, ensuring the bread fully absorbs the egg mixture. You can customize the vegetables and cheese to your preference.