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A hot and delicious all-in-one breakfast casserole fresh from the oven

All-in-One Breakfast Casserole

This all-in-one breakfast casserole is perfect for a crowd or meal prep. It features sausage, vegetables, bread, and cheese baked in an eggy custard.
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Prep Time 15 minutes
Cook Time 1 hour
Total Time 1 hour 15 minutes
Servings 8 servings
Calories 450 kcal

Equipment

  • large skillet
  • 9x13 inch baking dish
  • large bowl
  • whisk

Ingredients
  

Main Ingredients

  • 1 lb breakfast sausage Or bacon, ham, or a mix!
  • 1 cup chopped onion Yellow or white work best.
  • 1 cup chopped bell pepper Any color you prefer for sweetness and color.
  • 6 slices day-old bread Stale bread absorbs the custard better. You can also use hash browns or diced cooked potatoes.
  • 8 large eggs
  • 2 cups milk Whole milk for richness, but 2% works too.
  • 1 teaspoon salt Essential for seasoning.
  • 0.5 teaspoon black pepper Freshly ground is always best.
  • 1 teaspoon dry mustard Adds a subtle tang and depth of flavor.
  • 2 cups shredded cheddar cheese Or a blend of your favorite cheeses like Monterey Jack, Gruyere, or a Mexican blend.

Instructions
 

Preparation

  • Cook the breakfast sausage in a large skillet until browned, then drain excess grease.
  • Add chopped onion and bell pepper to the same skillet and cook until softened.
  • Tear day-old bread into bite-sized pieces and scatter in a greased 9x13 inch baking dish.
  • Evenly sprinkle the cooked sausage, onion, and bell pepper mixture over the bread.
  • Whisk eggs, milk, salt, pepper, and dry mustard in a large bowl until well combined.
  • Carefully pour the egg mixture over the ingredients in the baking dish, ensuring all bread is moistened.
  • Generously sprinkle shredded cheddar cheese over the top of the casserole.
  • Cover and refrigerate for at least 4 hours or overnight for best results.
  • Preheat oven to 350°F (175°C) and let casserole sit at room temperature for 20-30 minutes.
  • Bake uncovered for 45-60 minutes, or until set and golden brown.
  • Let the casserole rest for 5-10 minutes before slicing and serving.

Notes

For a make-ahead brunch, assemble the casserole the night before and bake it in the morning. Customize with your favorite vegetables or cheeses for endless variations.