Sausage Breakfast Casserole Recipe From Scratch

My sausage breakfast casserole is the one dish I make every Christmas morning. It feeds a crowd with minimal morning effort. Ground sausage, eggs, cheese, and bread bake together into a creamy, savory slab that holds its shape when sliced.

Why This Sausage Breakfast Casserole Works

The sausage fat does the heavy lifting here. After browning the ground sausage, I cook the onions in those drippings. Every bit of flavor soaks into the vegetables before they hit the egg mixture.

Cubed white bread acts as a sponge. It soaks overnight in the seasoned egg and milk custard. By morning the bread has absorbed everything and the casserole bakes up puffed and set with no soggy spots.

A full cup of shredded cheddar melts into every slice. The cheese creates a golden, bubbling top crust and a creamy interior that holds together when you cut and lift each piece.

Ingredients

• 1 pound ground breakfast sausage
• 6 large eggs
• 2 cups whole milk
• 1 teaspoon dry mustard powder
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 6 slices white sandwich bread, cubed into 1-inch pieces
• 1 cup shredded sharp cheddar cheese
• 1/2 medium yellow onion, diced
• 1/2 cup diced mushrooms

What You Need for Sausage Breakfast Casserole

Ground breakfast sausage — Jimmy Dean original or any seasoned pork sausage works. Spicy sausage adds heat if your crowd likes it. Turkey sausage is a leaner swap that holds together just as well.

Eggs — Six eggs give enough protein to set the custard firm without turning rubbery. Large eggs are standard; extra-large will make the casserole slightly taller.

Whole milk — Fat in whole milk keeps the custard creamy. Half-and-half makes it even richer. Two percent works but the texture is slightly less silky.

Dry mustard powder — A classic breakfast casserole seasoning. It adds a subtle tang that rounds out the sausage without tasting like mustard. Do not skip it.

White sandwich bread — Soft bread soaks up custard faster than sourdough or artisan bread. Day-old bread absorbs even better. Trim the crusts off if you prefer a more uniform texture.

Sharp cheddar cheese — Sharp cheddar has enough intensity to taste through the egg and sausage. Mild cheddar gets lost. A mix of cheddar and Gruyere adds complexity if you want to upgrade.

Mushrooms — Cooked in sausage drippings, they add earthiness and stretch the filling. Omit them if your family won’t eat them — the casserole is complete without.

How to Make Sausage Breakfast Casserole

1. Brown the ground sausage in a large skillet over medium heat, breaking it up as it cooks, about 8 minutes, until no pink remains. Transfer to a plate.
2. Add the diced onion and mushrooms to the skillet with the sausage drippings. Cook for 4 minutes until softened. Remove from heat.
3. In a large bowl, whisk together the eggs, whole milk, dry mustard powder, salt, and black pepper until fully combined.
4. Add the cubed bread to the egg mixture. Stir to coat every piece. Let it sit for 2 minutes so the bread starts absorbing the custard.
5. Add the cooked sausage, onion mixture, and half the shredded cheddar cheese to the bowl. Stir gently to combine.
6. Pour the mixture into a greased 9×13-inch baking dish. Spread evenly.
7. Sprinkle the remaining cheddar cheese over the top.
8. Cover with plastic wrap and refrigerate overnight, or for at least 4 hours.
9. Preheat oven to 350°F (175°C). Remove plastic wrap from the baking dish.
10. Bake uncovered for 45 minutes, until the top is golden and the center is set. A knife inserted in the center should come out clean.
11. Let rest for 5 minutes before slicing and serving.

Sausage Breakfast Casserole Variations

Spicy Sausage Breakfast Casserole

Swap the mild breakfast sausage for hot Italian sausage or chorizo. Add a diced jalapeño to the onion and mushroom step. The heat builds as it bakes and pairs well with a dollop of sour cream on top.

Hashbrown Sausage Breakfast Casserole

Replace the cubed bread with 2 cups of frozen shredded hashbrowns, thawed and pressed dry. The potatoes crisp on the bottom during baking and give the casserole a heartier texture. Great for gluten-sensitive guests.

Low-Carb Sausage Breakfast Casserole

Skip the bread entirely and double the sausage and cheese. The egg custard sets firm without a starch base. The texture is denser, closer to a frittata. Add diced bell peppers for color and volume.

Croissant Sausage Breakfast Casserole

Use torn croissant pieces instead of sandwich bread. Croissants are buttery and layered. They soak up the custard but stay slightly flaky on top after baking. This version is richer and works well for a holiday brunch.

Tips for the Best Sausage Breakfast Casserole

• I always assemble the sausage breakfast casserole the night before so the bread absorbs the custard fully. Morning assembly gives a wetter result.
• Press the bread cubes down gently after pouring into the dish to make sure every piece is coated.
• Let the casserole rest 5 minutes after baking before slicing. Cutting too early causes it to fall apart.
• Use an instant-read thermometer — the center should reach 165°F (74°C) to confirm the eggs are fully set.
• Double the recipe and bake in two dishes for groups over 12. Bake time stays the same at 45 minutes.
• Salsa, hot sauce, or fresh chives on top add brightness to each slice.

Make Ahead & Storage

This sausage breakfast casserole is built for make-ahead prep. Assemble the night before and refrigerate overnight. Pull it straight from the fridge into the preheated oven the next morning — no thawing needed.

Leftovers keep in the fridge for up to 4 days in an airtight container. Reheat individual slices in the microwave for 90 seconds or in a 325°F oven for 12 minutes. To freeze, wrap individual slices in plastic wrap and seal in a zip bag. Frozen slices last up to 2 months and reheat from frozen at 350°F for 20 minutes.

Common Questions

Can I make sausage breakfast casserole without bread?

Yes. Skip the bread and replace it with thawed frozen hashbrowns or simply leave it out for a lower-carb version. The eggs and cheese set firm enough to hold without a starch base. The texture is denser but slices cleanly.

How long does sausage breakfast casserole need to soak?

A minimum of 4 hours gives the bread enough time to absorb the egg custard. Overnight is ideal. I have assembled it in the morning and baked immediately — it works, but the texture is slightly uneven.

Can I use turkey sausage in breakfast casserole?

Yes. Turkey sausage is leaner and slightly drier, so the casserole may be a touch less rich. Season it well before browning since it has less fat to carry flavor. The bake time stays the same at 45 minutes.

What is the best cheese for breakfast casserole?

Sharp cheddar is my first choice. It melts well and has enough bite to stand out against the egg and sausage. Gruyere, pepper jack, or a Mexican blend all work. Avoid pre-sliced cheese — it doesn’t melt as evenly as shredded.

Can I freeze sausage breakfast casserole before baking?

Yes. Assemble the casserole, cover tightly, and freeze unbaked for up to 1 month. Thaw in the refrigerator overnight, then bake as directed at 350°F for 45 to 50 minutes. Check the center with a knife before pulling from the oven.

This sausage breakfast casserole from scratch is the recipe I reach for every holiday morning and weekend brunch. Save it now and come back when you need to feed a crowd with almost no morning effort.