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Croissant Breakfast Casserole with Savory Sausage and Cheddar Recipe

5 Stars 4 Stars 3 Stars 2 Stars 1 Star 4.3 from 78 reviews
  • Author: Lily
  • Prep Time: 20 minutes
  • Cook Time: 45 minutes
  • Total Time: 9 hours 30 minutes
  • Yield: 12 servings
  • Category: Breakfast Casserole
  • Method: Baking
  • Cuisine: American

Description

A hearty and savory Croissant Breakfast Casserole layered with browned breakfast sausage, sautéed onions, shredded cheddar, and torn croissants soaked in a spiced egg and milk mixture. This casserole is baked until golden and served warm with a rich, creamy sausage gravy made from reserved sausage fat, butter, and milk. Perfect for make-ahead breakfasts or brunches, it’s comforting, flavorful, and ideal for feeding a crowd.


Ingredients

Scale

Casserole Base

  • 1 tablespoon olive oil
  • 1 small onion, peeled and diced
  • 1 pound breakfast sausage (mild flavor)
  • 4 large croissants or 8 small croissants, torn into large bite-size pieces
  • 1 cup shredded cheddar cheese

Egg Mixture

  • 6 large eggs
  • ½ cup heavy whipping cream
  • ½ cup whole milk (from the total 3 cups)
  • ½ teaspoon dry mustard powder
  • ½ teaspoon salt, plus additional to taste
  • ½ teaspoon black pepper, plus additional to taste
  • ¼ teaspoon paprika
  • ¼ teaspoon garlic powder

Sausage Gravy

  • 2 tablespoons butter
  • 1 tablespoon reserved sausage fat (from cooking sausage)
  • 3 tablespoons all-purpose flour
  • 2 ½ cups whole milk (remaining from the total 3 cups)
  • Salt and pepper to taste


Instructions

  1. Sauté Onions and Cook Sausage: Heat the olive oil in a large skillet over medium heat. Add the diced onions and sauté until they become soft and translucent, about 3 to 5 minutes. Then crumble in the breakfast sausage and cook until browned and fully cooked through, with no pink remaining. Drain excess fat into a small container and refrigerate to save for later sausage gravy.
  2. Assemble Casserole Base: In a large bowl, combine the cooked sausage and onions with the torn croissants and shredded cheddar cheese, stirring gently to distribute evenly. Transfer this mixture into a greased 9×13-inch glass baking dish prepared with non-stick spray.
  3. Prepare Egg Mixture: In a medium bowl, whisk together the eggs, heavy cream, ½ cup milk, dry mustard powder, salt, black pepper, paprika, and garlic powder until smooth and well combined.
  4. Combine Egg Mixture with Casserole: Pour the egg mixture evenly over the croissant and sausage mixture in the baking dish, making sure all pieces are thoroughly coated with the egg mixture.
  5. Refrigerate Overnight: Cover the casserole dish tightly with plastic wrap and chill in the refrigerator for at least 8 hours or overnight to allow the croissants to soak up the flavors and egg mixture fully.
  6. Preheat Oven and Bake: When ready to bake, remove the casserole from the refrigerator and preheat the oven to 350°F (175°C). Bake the casserole uncovered for 35 to 45 minutes, or until the top is golden brown and the eggs are completely set.
  7. Make Sausage Gravy: While the casserole bakes, melt the butter and 1 tablespoon reserved sausage fat together over medium heat in a saucepan. Whisk in the flour and cook for about 1 minute, stirring constantly to create a roux.
  8. Add Milk and Thicken Gravy: Gradually pour in the remaining 2 ½ cups milk, whisking continuously to prevent lumps. Cook on low heat, stirring frequently for 2 to 3 minutes until the gravy thickens. Season with salt and pepper to taste.
  9. Serve: Once baked, slice the casserole into portions and serve warm with the creamy sausage gravy ladled over the top or served on the side.

Notes

  • Make sure to refrigerate the casserole overnight for best texture and flavor absorption.
  • Use mild breakfast sausage for a balanced flavor, but spicy sausage can be substituted if preferred.
  • The reserved sausage fat adds rich flavor to the gravy – don’t discard it.
  • Leftovers can be refrigerated for up to 3 days and reheated gently.
  • Gluten-free croissants or bread can be used as a substitute if desired.