I make this casserole whenever I need a low-effort, crowd-pleasing breakfast that practically makes itself. It’s an overnight breakfast casserole with sausage, eggs, and melty cheese—perfect for busy mornings, holiday brunches, or when friends crash at your place. The beauty is the prep: cook the sausage, mix, refrigerate, and wake up to a ready-to-bake dish. If you enjoy make-ahead breakfasts, you might also like this ultimate make-ahead breakfast casserole for more planning-friendly ideas.
Why you’ll love this dish
This casserole checks a lot of boxes: simple prep, feeds a crowd, and uses pantry basics. It’s budget-friendly because bread stretches the protein, flexible because you can swap cheeses or herbs, and kid-approved thanks to the gooey cheese and familiar flavors. Make it for weekend brunch, potlucks, or a week of easy breakfasts — it reheats beautifully.
"I made this for Sunday brunch and woke up to the smell of baked cheese and sausage. The texture was custardy, and everyone went back for seconds." — a satisfied home cook
The cooking process explained
Quick overview: brown the sausage and cool it slightly. Whisk eggs with milk and dry mustard for a savory custard. Toss in cubed day-old bread and the cooked sausage so everything soaks up the egg mixture. Transfer to a greased 9×13-inch pan, top with shredded cheese, cover, and chill overnight. Bake the next morning until golden and set.
This short workflow helps you plan when to cook, what to chill, and what to do in the morning.
What you’ll need
- 1 pound mild or spicy sausage (your choice of heat)
- 6 large eggs
- 2 cups shredded cheese (cheddar, Monterey Jack, or a blend)
- 2 teaspoons dry mustard
- 1 cup milk
- Salt and freshly ground black pepper to taste
- 1 loaf stale or day-old bread, cubed (sourdough, French, or challah)
- Fresh herbs for garnish (parsley or chives)
Ingredient notes: Use day-old bread so it soaks the custard without turning mushy. If you prefer a lighter milk, 2% works fine. Dry mustard adds a subtle tang without altering texture. If you want lower sodium, pick a reduced-salt cheese and adjust seasoning at the end.
Step-by-step instructions
- Preheat the oven to 350°F (175°C). Grease a 9×13-inch baking dish.
- Heat a large skillet over medium. Add the sausage and cook until well browned. Scoop sausage into a bowl and let cool slightly. Drain any excess fat if needed.
- In a mixing bowl, whisk together the eggs, milk, dry mustard, salt, and pepper until smooth.
- Add the cubed bread and cooked sausage to the egg mixture. Stir gently to coat the bread. Let the mixture rest for a few minutes so the bread soaks up the custard.
- Transfer everything to the prepared baking dish and spread evenly. Sprinkle the shredded cheese over the top.
- Cover the dish and refrigerate overnight, or for at least 6 hours.
- The next morning, remove the cover and bake uncovered for 45 to 50 minutes. The casserole is done when it is golden on top and set in the center. If you use a thermometer, the internal temperature should reach about 160°F.
- Let the casserole rest for 5 to 10 minutes before cutting. Garnish with fresh parsley or chives and serve.
Serving suggestions
Pair slices with bright, fresh sides to balance the richness. Try a simple fruit salad, roasted tomatoes, or a mixed green salad with a light vinaigrette. For a cozy brunch table, warm biscuits or buttered toast work well. If you want more brunch ideas, consider this fruity twist like an overnight blueberry French toast casserole for a sweeter option on the same spread.
Storage and reheating tips
Cool the casserole to room temperature no longer than two hours after baking. Store leftovers in an airtight container in the refrigerator for 3 to 4 days. To reheat, warm individual slices in the microwave for 60 to 90 seconds, or reheat a baking dish at 350°F until warmed through, about 15 to 20 minutes. To freeze, wrap portions tightly in plastic and foil or use freezer-safe containers; freeze for up to 2 months. Thaw in the refrigerator overnight before reheating.
Pro chef tips
- Use day-old or slightly stale bread for the best texture. Fresh loaf will make the casserole gummy.
- Let the bread sit in the egg mixture for at least 5 minutes to soak up custard; this improves the custardy interior.
- Drain excess fat from the sausage so the casserole isn’t greasy. Spoon off fat or blot with paper towel after browning.
- Cover the dish while refrigerating to prevent the bread from drying out and to avoid fridge odors.
- If the top browns too fast while baking, tent loosely with foil for the remaining time.
Flavor swaps
- Vegetable-forward: Swap sausage for sautéed mushrooms, spinach, and bell peppers. Add a little smoked paprika for depth.
- Cheese variations: Use pepper jack for heat, Swiss for a nutty note, or a sharp cheddar for stronger flavor.
- Herb-forward: Stir chopped dill or tarragon into the egg mixture for a fresh twist.
- Make it lighter: Use whole-wheat or multigrain bread and low-fat cheese and milk.
Common questions
How long does it take to prep and cook this casserole?
Active prep is about 20 to 30 minutes. The casserole needs 6+ hours of refrigeration overnight. Baking is 45 to 50 minutes. Plan for about 1 hour of hands-off cooking time the next morning.
Can I make this casserole vegetarian?
Yes. Replace the sausage with a cooked plant-based sausage or a hearty mix of sautéed mushrooms, onions, and bell peppers. Adjust seasoning to taste.
Is it safe to refrigerate the assembled casserole overnight?
Yes. Cover the dish and refrigerate within two hours of assembly. Proper refrigeration prevents bacterial growth. Bake the next day until the center is set and reaches a safe temperature.
Can I assemble and freeze before baking?
You can freeze the assembled, unbaked casserole. Wrap tightly and freeze up to 2 months. Thaw overnight in the refrigerator before unwrapping and baking as directed.
What if my bread soaks up all the egg and looks dry?
If the bread seems dry after the initial soak, gently press down to help it absorb more liquid. If it still seems dry, whisk an extra egg with a splash of milk and pour over before baking.
Overnight Breakfast Casserole with Sausage, Eggs, and Cheese
Ingredients
Method
- Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking dish.
- Heat a large skillet over medium. Add the sausage and cook until well browned. Scoop sausage into a bowl and let cool slightly. Drain any excess fat if needed.
- In a mixing bowl, whisk together the eggs, milk, dry mustard, salt, and pepper until smooth.
- Add the cubed bread and cooked sausage to the egg mixture. Stir gently to coat the bread. Let the mixture rest for a few minutes so the bread soaks up the custard.
- Transfer everything to the prepared baking dish and spread evenly. Sprinkle the shredded cheese over the top.
- Cover the dish and refrigerate overnight, or for at least 6 hours.
- The next morning, remove the cover and bake uncovered for 45 to 50 minutes until golden on top and set in the center. The internal temperature should reach about 160°F.
- Let the casserole rest for 5 to 10 minutes before cutting. Garnish with fresh parsley or chives and serve.
