Description

This Croissant Breakfast Casserole with Savory Sausage and Cheddar is a hearty and flavorful make-ahead breakfast dish perfect for busy mornings or brunch gatherings. Tender croissant pieces soaked in a rich egg and milk mixture, combined with browned breakfast sausage, sautéed onions, and melted cheddar cheese, create a delightful layered casserole. The dish is baked until golden and set, then served with a creamy homemade sausage gravy made from reserved sausage fat, butter, flour, and milk, adding an extra savory touch. Refrigerating overnight ensures the croissants absorb all the flavors for a custardy texture that’s both comforting and indulgent.

Ingredients

Scale

Casserole Ingredients

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
6 large eggs
½ cup heavy whipping cream
3 cups whole milk, divided
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 Ingredients

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

Cook Mode Prevent your screen from going dark

Instructions

Sauté Onions and Cook Sausage: In a large skillet, heat olive oil over medium heat. Add diced onions and sauté until softened and translucent, about 3-5 minutes. Crumble the sausage into the pan, cooking until browned and no longer pink inside. Drain excess fat into a small container and refrigerate overnight for gravy use.
Assemble Casserole Base: In a large bowl, combine the cooked sausage and onions with the torn croissants and shredded cheddar cheese. Stir gently to mix. Transfer this mixture into a greased 9×13-inch glass baking dish prepared with non-stick spray.
Prepare Egg Mixture: In a medium bowl, whisk together the eggs, heavy cream, ½ cup of the milk, dry mustard powder, salt, black pepper, paprika, and garlic powder until smooth and fully combined.
Combine Egg Mixture with Casserole: Pour the egg mixture evenly over the croissant and sausage mixture in the baking dish, making sure all croissant pieces are well coated.
Refrigerate Overnight: Cover the casserole dish with plastic wrap and chill in the refrigerator for at least 8 hours or overnight to allow the croissants to absorb the egg mixture thoroughly.
Preheat Oven and Bake: Remove the casserole from the refrigerator and preheat the oven to 350°F (175°C). Bake uncovered for 35-45 minutes or until the casserole is golden brown and the eggs are fully set.
Make Sausage Gravy: While the casserole bakes, melt butter and 1 tablespoon of the reserved sausage fat over medium heat in a saucepan. Whisk in the flour to form a roux and cook for 1 minute, stirring constantly to avoid lumps.
Add Milk and Thicken Gravy: Gradually whisk in the remaining 2 ½ cups of whole milk a little at a time, ensuring it is fully incorporated before adding more. Continue cooking on low heat for 2-3 minutes, stirring often until the gravy thickens. Season with salt and pepper to taste.
Serve: Slice the baked casserole into portions and serve warm, with the creamy sausage gravy ladled over each slice or on the side.

Notes

For best results, refrigerate the casserole overnight to allow the croissants to soak up the egg mixture fully, resulting in a custard-like texture.
You can substitute mild breakfast sausage with spicy sausage for a kick of heat.
If preferred, use whole wheat flour for the gravy to add a bit of fiber.
Leftover casserole can be refrigerated for up to 3 days and reheated in the oven or microwave.
To make ahead, prepare the casserole base and egg mixture the night before and assemble shortly before baking the next morning.