Name: Make-Ahead Breakfast Casserole with Sausage and Cheddar Recipe
Prep time: 20 min
Cook time: 50 min
Total time: 70 min
Ingredients: 1 lb bulk breakfast sausage; 1 tablespoon olive oil (if needed); 8 cups cubed day-old bread; 2 cups shredded sharp cheddar cheese; 8 large eggs; 2 cups whole milk; 1 teaspoon kosher salt; 1/2 teaspoon black pepper; 1/2 teaspoon dry mustard powder; 2 green onions, thinly sliced (optional)

This make-ahead breakfast casserole with savory sausage and sharp cheddar is built for mornings when you want something hot and homemade without the work. Assemble it the night before, let the bread soak up the eggy custard, and bake it off in the morning.

It comes out puffy and golden, with a creamy center and crisp edges. This one works whether you are hosting a slow weekend brunch or just trying to get a warm breakfast on the table before the day runs away from you.

Why This Casserole Works

I keep coming back to this recipe because the overnight soak does all the heavy lifting. The bread drinks up the egg mixture and turns into a soft custard that bakes up with a crackly, deep golden top.

The sausage and cheddar make it hearty enough to hold everyone over until lunch, and the flavor is simple but satisfying. It is forgiving, too. You can swap the meat, the cheese, or toss in some extra vegetables and it still holds together.

Ingredients

1 lb bulk breakfast sausage: or uncooked sausage links, casings removed
1 tablespoon olive oil: only if your sausage is very lean
8 cups cubed day-old bread: from about 1 large loaf, crusts on or off
2 cups shredded sharp cheddar cheese: 8 oz
8 large eggs
2 cups whole milk
1 teaspoon kosher salt
1/2 teaspoon black pepper
1/2 teaspoon dry mustard powder: optional, adds a subtle tang
2 green onions, thinly sliced: for serving, optional

Variations / Substitutions

Swap the sausage for bacon: cook 8 slices until crisp, crumble, and use in place of the sausage. The texture will be a little chewier.
Make it vegetarian: skip the meat and sauté 8 oz sliced mushrooms and a chopped bell pepper in olive oil until soft, then layer as directed.
Change the cheese: sharp cheddar is classic, but pepper Jack adds gentle heat, and Swiss or Gruyère melt beautifully.
Go dairy-free: use unsweetened almond milk and a plant-based shredded cheese that melts well. The custard will be slightly less rich.

If you are feeding a crowd, our Sausage and Egg Breakfast Burritos are another great make-ahead option.

How to Make Make-Ahead Breakfast Casserole

Step 1: Brown the Sausage

If your sausage is in links, remove the casings first. Heat a large skillet over medium-high heat and add the sausage, breaking it into crumbles with a wooden spoon. Cook until no pink remains, about 6 to 8 minutes. If the sausage is very lean, add 1 tablespoon olive oil to keep it from sticking.

You want the crumbles to be lightly browned in spots. That browning adds a deeper savory flavor to the finished casserole. Transfer the cooked sausage to a paper towel-lined plate to drain and let it cool slightly while you assemble.

Step 2: Assemble the Casserole

Grease a 9×13-inch baking dish with butter or cooking spray. Spread half of the bread cubes in an even layer across the bottom. Top with half of the cooked sausage and half of the shredded cheddar. Repeat with the remaining bread, sausage, and cheese, creating two layers that help the custard distribute evenly.

In a large bowl, whisk together the 8 eggs, 2 cups milk, 1 teaspoon salt, 1/2 teaspoon pepper, and the dry mustard, if using, until smooth. Pour the egg mixture slowly and evenly over the casserole, making sure to wet all the bread. Press down gently with a spatula so the top layer soaks up some of the liquid. Cover the dish tightly with plastic wrap and refrigerate for at least 4 hours, or overnight up to 12 hours.

Step 3: Bake the Casserole

When you are ready to bake, take the casserole out of the fridge while you preheat the oven to 375°F (190°C). Remove the plastic wrap and let the dish sit at room temperature for about 20 minutes while the oven heats. That brief rest helps it bake more evenly.

Bake uncovered until the center is set and the top is puffed and deep golden brown, 45 to 55 minutes. The edges will look crispy and start pulling away from the sides of the dish. If the top is browning too quickly before the center is done, tent it loosely with foil for the last 10 minutes.

Step 4: Rest and Serve the Casserole

Remove the casserole from the oven and let it rest on a wire rack for about 10 minutes. This little pause allows the custard to finish setting so it slices cleanly.

Tips for a Perfect Breakfast Casserole

Use day-old bread: it absorbs the custard without turning to mush. If you only have fresh bread, tear it and leave it out on a baking sheet for an hour to dry a little.
Don’t rush the soak: even a couple of hours in the fridge makes a difference, but the full 8 to 12 hours gives you that velvety custard texture.
Watch the top while it bakes: if it gets deep brown before the 45-minute mark, tent it loosely with foil. You still want that crisp top, so uncover it again for the final 5 minutes if you tented early.
Let it sit before slicing: the 10-minute rest after baking is not just for cooling. Trying to cut it right out of the oven will leave you with a puddle on the plate.

Baking time can vary depending on whether your dish goes straight from the fridge to the oven. Here is a quick guide:

Casserole State	Oven Temp	Approx. Bake Time
Fridge-cold, unwrapped	375°F (190°C)	55 to 65 minutes
Room temperature, sat out 20 to 30 minutes	375°F (190°C)	45 to 55 minutes

Storing Leftovers

Refrigerate: store leftovers tightly covered in the fridge for up to 3 days.
Reheating: warm individual portions in the microwave for 1 to 2 minutes, or cover the whole dish with foil and reheat in a 325°F oven for 15 to 20 minutes.

Frequently Asked Questions

Can I freeze this breakfast casserole?

Yes. Assemble the casserole without baking, wrap it tightly in plastic and then foil, and freeze for up to 2 months. Thaw overnight in the fridge, then bake as directed, adding about 10 extra minutes to the bake time.

Do I really need to refrigerate it overnight?

The overnight soak is not strictly required, but it is what gives the casserole its creamy custard texture. If you are in a rush, let it sit in the fridge for at least 1 hour before baking. It will still work, just with a slightly less tender result.

Can I make this without bread?

If you would rather skip the bread, you can use 6 cups of cubed and steamed potatoes instead. Par-cook the potatoes until just tender, then layer them the same way. The bake time will be about the same.

What if I only have egg whites?

You can replace half the eggs with egg substitute, but using all egg whites makes the casserole less rich. Whole eggs give the best texture and flavor here.