Sausage Egg and Cheese Breakfast Casserole (Overnight) | Easy Make-Ahead Recipe

Sausage Egg and Cheese Breakfast Casserole

This make-ahead sausage, egg, and cheese breakfast casserole is a reliable go-to for holiday mornings, brunch, and easy weekend breakfasts.

It’s assembled the night before with bread cubes, sausage, eggs, cheddar, and mushrooms—then finished with a creamy soup topping and baked low and slow until hot and set.

🍳 Sausage, Egg & Cheese Breakfast Casserole

The ultimate make-ahead holiday brunch tradition. Layers of cubed bread, savory sausage, and mushrooms soaked overnight in a mustard-egg custard, finished with a velvety cream canopy.

⏱️ Bake Time: 2 to 2 ½ Hours 🌙 Prep: Overnight Rest Required 🍽️ Servings: 8 to 10 🍳 Pan: 13×9-inch Baking Pan

Ingredients

The Casserole Layers:

  • 8 slices bread (cubed)
  • 2 cups cheddar cheese (grated)
  • 1 ½ to 2 lb link sausage (cut up and fried beforehand)
  • Fresh mushrooms (or 1 can mushrooms, drained)

The Egg Custard & Topping:

  • 6 eggs
  • 2 ½ cups milk
  • ¾ teaspoon dry mustard
  • ½ can cream of mushroom soup
  • Extra milk (to dilute the soup 2:1)

Preparation & Cooking

🌡️ Oven Temp: 300°F (Low & Slow)

  1. Layer the Pan: Grease a large casserole dish or standard 13×9-inch baking pan. Distribute half of the cubed bread evenly across the bottom. Top with half of the grated cheddar cheese, followed by all of your fried sausage pieces and mushrooms.
  2. Seal the Top: Scatter the remaining cubed bread over the sausage layer, then finish by capping it with the remaining grated cheddar cheese.
  3. Pour Custard & Chill: Whisk the 6 eggs together with 2 ½ cups of milk and the ¾ teaspoon of dry mustard until smooth. Pour this mixture evenly over the entire casserole. Cover closely and refrigerate overnight to let the bread completely absorb the custard.
  4. The Next Day: Preheat your oven to a gentle 300°F. Thoroughly mix the ½ can of cream of mushroom soup with enough milk to dilute it (using a 2 parts soup to 1 part milk ratio) until smooth. Drizzle this evenly over the top of the set casserole.
  5. Bake & Rest: Bake uncovered at 300°F for 2 to 2 ½ hours. Let the dish rest on a cooling rack for 5 to 10 minutes to set cleanly before slicing and serving hot.

Breakfast Casserole FAQ

Do I have to refrigerate it overnight?

Overnight is best so the bread absorbs the egg mixture evenly, but you can refrigerate at least 4 hours if needed.

Can I use breakfast sausage patties instead of links?

Yes. Cook first, then crumble or chop and use the same way.

Do I bake it covered or uncovered?

Bake uncovered at 300°F so the top can brown lightly while the center sets.

How do I know when it’s done?

The center should be set and hot throughout. Let it rest 5 to 10 minutes before slicing.

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