This recipe gives you a homemade breakfast casserole that actually works on busy mornings.
You learn how to layer sausage, eggs, milk, and bread or croissants into one dish that chills overnight and bakes golden the next day.
People look for the best breakfast casserole because they want something reliable. This one is simple, filling, and makes mornings calmer. You set it up the night before and let the oven do the work while you pour coffee. I’ve made it on holidays, on ordinary weekends, and even for a breakfast brunch with neighbors. Each time, it delivers steady results.
The casserole belongs on any list of easy breakfast casseroles. It feels homemade without requiring much from you. The flavors are comforting, the method is forgiving, and the outcome looks like you fussed, even though you didn’t.
Why These Ingredients Make a Difference
Eggs set the foundation. Eight large eggs whisked with milk create the custard that holds everything together. I always use whole milk because it gives a richer bake, and the texture comes out smoother compared to reduced fat.
The sausage brings depth. Breakfast sausage, browned and crumbled, infuses the bread with savory flavor. If you prefer, turkey sausage works too, but pork gives the boldest taste.
Bread or croissants decide the texture. Day-old bread cubes absorb the custard without turning mushy. Croissants, on the other hand, add a buttery lightness that feels more indulgent. Both work, but they produce very different casseroles.
Cheddar and mozzarella form the top layer of flavor. I like the balance. Cheddar melts sharp and gooey, while mozzarella adds that stretchy bite.
For garnish, fresh chives or parsley cut through the richness. I rarely skip it, even if it’s just a quick sprinkle.
If you enjoy recipes with layered bread and creaminess, you might also want to look at my Blueberry Cream Cheese Croissant Casserole.
Bread vs Croissant: Which Works Better?
I’ve tested both, and my notes always remind me how much the base changes the outcome. Bread, especially French bread or brioche, makes a sturdier casserole. It soaks the egg mixture evenly and slices neatly. Croissants give a softer structure. They turn almost pastry-like once baked, buttery and light, though sometimes a little harder to cut cleanly.
If you want a traditional look and a slice-and-serve consistency, bread is the safer choice. For holidays or when you want something more decadent, croissants turn it into a bakery-style dish. Personally, I use bread for big family breakfasts and croissants for smaller gatherings where presentation matters more.
How to Assemble with Ease
Cooking the sausage first is crucial. You want it browned, crumbly, and cooled a bit so it doesn’t steam the bread. I drain off extra grease because too much oil makes the bottom soggy.
Cubing the bread or croissants is the next step. If the bread is very fresh, I toast the cubes lightly in the oven. This helps them hold their shape once the custard is poured over.
Mixing the eggs, milk, Dijon mustard, and seasonings comes next. Dijon mustard might sound unusual, but it sharpens the flavor without standing out. I learned this trick years ago from a chef who insisted on mustard in egg bakes, and I’ve kept it ever since.
The Overnight Step That Brings Success
Refrigeration overnight isn’t optional in my kitchen. It gives the bread time to fully absorb the custard. Skipping this step makes the center uneven. By morning, the casserole feels unified, ready to bake without surprises.
Cover the dish tightly. Plastic wrap or foil keeps the moisture where it belongs. Place it on a flat shelf so the mixture soaks evenly.
I’ve made this casserole ahead for up to 24 hours, and it baked just as well. That flexibility is what makes it one of the best make ahead breakfast casseroles I know.
If you want another simple make ahead idea, my Tater Tot Breakfast Casserole also holds beautifully overnight.
Baking Notes for a Golden Finish
Bring the dish out of the refrigerator while the oven heats. Letting it rest at room temperature for 15 minutes prevents uneven cooking. Bake uncovered until the top is golden and the center is set.
Testing for doneness is simple. Insert a knife near the middle. If it comes out clean, the casserole is ready. If the knife looks wet, give it another few minutes.
After baking, I always wait 10 minutes before slicing. This resting time firms up the custard and makes cutting smoother. Garnish with chives or parsley for freshness, then serve while warm.
If you enjoy a lighter morning option, you may like my Sweet Potato Pancakes. They balance savory casseroles beautifully.
Serving and Storing for Later
Serve this casserole straight from the dish. A metal spatula lifts neat squares. I pair it with fruit salad or roasted vegetables if serving at brunch.
For storage, cover leftovers tightly and refrigerate for up to three days. Reheat individual slices in the oven for best texture. Microwaves work in a pinch, though they soften the edges.
I’ve also frozen baked slices. Wrap them well, thaw in the fridge, then warm in the oven. The flavor holds, and the texture stays satisfying.
Save This Recipe and Join the Conversation
This overnight breakfast casserole belongs in your recipe rotation. It’s practical, forgiving, and consistently delivers. You set it up in minutes, and the morning greets you with a hot meal ready to serve.
I’d love for you to save this recipe to your Pinterest board. It makes holiday mornings and weekend brunches easier. Share in the comments how it turned out for you, or let me know if you chose bread or croissants. Community tips often inspire me to try something new myself.
Easy Overnight Breakfast Casserole
Overnight breakfast casserole layers cubed bread or croissants with sausage, eggs, milk, and cheese for a savory bake that sets overnight. I assemble it in the evening, let it chill, and bake it fresh in the morning until golden. It’s one of my favorite breakfast recipes casserole-style for holidays or slow weekends. This homemade breakfast casserole is easy to prep and feeds a crowd without stress. I keep it in my best breakfast casserole list because it checks every box: simple ingredients, big flavor, minimal morning effort. If you’re planning a make ahead breakfast casserole or looking for overnight breakfast ideas for guests, this is the one I go back to every time.
Ingredients
- 8 large eggs
- 2 cups whole milk
- 1 tsp salt
- ½ tsp black pepper
- ½ tsp garlic powder
- 1 tsp Dijon mustard
- 1 lb breakfast sausage, cooked and crumbled
- 6 cups cubed day-old bread (such as French bread, brioche, or croissants)
- 1 ½ cups shredded cheddar cheese
- ½ cup shredded mozzarella cheese
- Chopped chives or parsley, for garnish (optional)
Instructions
- COOK THE SAUSAGE: In a large skillet over medium heat, cook the sausage until browned and fully cooked, breaking it into small crumbles as it cooks. Drain any excess grease and set aside to cool slightly.
- PREPARE THE BREAD: Cube the bread into bite-sized pieces. If the bread is very fresh, spread the cubes on a baking sheet and toast them at 300°F (150°C) for 8–10 minutes until lightly dried. This helps the bread absorb the egg mixture more evenly.
- MAKE THE EGG MIXTURE: In a large mixing bowl, whisk together the eggs, whole milk, salt, black pepper, garlic powder, and Dijon mustard until the mixture is completely smooth and well combined.
- ASSEMBLE THE CASSEROLE: Lightly grease a 9x13-inch baking dish. Spread the cubed bread evenly in the bottom of the dish. Sprinkle the cooked sausage over the bread layer. Add the shredded cheddar and mozzarella cheeses on top. Pour the egg mixture evenly over all ingredients, making sure the bread is well soaked. Press the bread down gently with a spatula if needed.
- REFRIGERATE OVERNIGHT: Cover the baking dish tightly with plastic wrap or foil and refrigerate for at least 8 hours or overnight to allow the egg mixture to fully absorb into the bread.
- BAKE THE NEXT MORNING: Preheat the oven to 350°F (175°C). Remove the casserole from the refrigerator and let it sit at room temperature while the oven heats. Bake uncovered for 45–55 minutes, or until the center is fully set and the top is golden brown. Let the casserole cool for 10 minutes before slicing. Garnish with chopped chives or parsley if desired and serve warm.
Notes
Use day-old bread for best texture; avoid very soft or fresh bread as it may become soggy.
• Turkey sausage or vegetarian sausage can be substituted for pork.
• This casserole can be assembled up to 24 hours in advance and baked straight from the fridge.
