If you’re looking for a comforting and effortlessly delicious morning meal, this Easy Overnight Breakfast Casserole Recipe is an absolute game-changer. With layers of savory sausage, soft cubed bread, melty cheddar, and a rich custard that soaks in all the flavors overnight, it’s like breakfast magic waiting for you in the morning. This casserole not only saves time during busy mornings but also fills your kitchen with an irresistible aroma that makes waking up something to look forward to.

Easy Overnight Breakfast Casserole Recipe - Recipe Image

Ingredients You’ll Need

The magic of this Easy Overnight Breakfast Casserole Recipe lies in its simple yet intentional ingredients, each bringing a unique texture, flavor, or color that makes every bite satisfying. From the savory punch of breakfast sausage to the creamy custard base, every component plays its part perfectly.

1 pound breakfast sausage: Provides hearty, savory flavor and a lovely meaty texture to the dish.
1/2 onion, chopped: Adds a slight sweetness and depth when softened with the sausage.
6 eggs: The rich binder that holds the casserole together while adding creaminess.
1 1/2 cups milk of choice: Keeps the casserole moist and tender; you can use dairy or any plant-based milk.
1 teaspoon mustard powder: Delivers a subtle zing that enhances the overall flavor without overpowering.
Salt and pepper to taste: Essential seasonings that bring balance and brightness to the dish.
4 cups cubed bread: The comforting foundation that soaks up the egg mixture, providing texture and structure.
1 cup shredded cheddar cheese: Melts beautifully for that golden, cheesy topping that’s utterly irresistible.
Optional chopped bell peppers, spinach, mushrooms: These veggies add color, nutrition, and an extra layer of flavor if you want to customize your casserole.

How to Make Easy Overnight Breakfast Casserole Recipe

Step 1: Cook the Sausage and Onions

Begin by heating a skillet over medium heat and cooking the breakfast sausage along with the chopped onion. Stir occasionally until the sausage is nicely browned and the onions become soft and translucent. This step unlocks deep flavors and ensures the sausage is perfectly cooked. Don’t forget to drain off any excess fat to keep the casserole from becoming greasy.

Step 2: Whisk Together the Egg Mixture

While the sausage cooks, grab a large bowl and whisk together the eggs, milk, mustard powder, salt, and pepper. This combination forms the luscious custard that will soak into the bread cubes and sausage, creating that classic breakfast casserole texture everyone loves.

Step 3: Assemble the Casserole Layers

Grease a 9 by 13-inch baking dish to prevent sticking, then start layering. First, spread the cubed bread evenly across the dish. Next, sprinkle the sausage and onion mixture on top, followed by the shredded cheddar cheese. If you’re feeling adventurous, add your optional chopped bell peppers, spinach, or mushrooms now to brighten up the dish both visually and in flavor.

Step 4: Pour the Egg Mixture Over

Carefully pour the prepared egg mixture evenly over the assembled bread and sausage layers. Take a moment to gently press down so the bread can absorb the liquid, ensuring every bite is moist and bursting with flavor.

Step 5: Refrigerate Overnight

Cover the baking dish tightly with plastic wrap or foil and pop it in the refrigerator overnight. This chilling time is crucial as it allows the bread to soak up all the custardy goodness, melding the flavors beautifully and setting a perfect texture for baking.

Step 6: Preheat the Oven

In the morning, remove the casserole from the fridge and preheat your oven to 350°F (175°C). This gentle heat will cook the eggs through without drying out the dish.

Step 7: Bake Until Golden and Set

Bake the casserole uncovered for 45 to 50 minutes, or until the top is golden brown and the center is fully set. Keep an eye on it during the last few minutes to ensure it doesn’t overcook. The aroma at this point will be simply irresistible.

Step 8: Cool Slightly Before Serving

Once baked, let the casserole sit for about 5 to 10 minutes before slicing. This resting time helps it firm up so your slices hold together nicely and makes serving a breeze.

How to Serve Easy Overnight Breakfast Casserole Recipe

Garnishes

A sprinkle of freshly chopped parsley or green onions adds a burst of color and a hint of freshness that brightens up each slice. If you’re a fan of heat, a dash of hot sauce or a smear of salsa on the side complements the casserole beautifully.

Side Dishes

This casserole pairs wonderfully with fresh fruit salad for a vibrant contrast or a crisp green salad if you want a lighter option. For a truly indulgent weekend brunch, serve with warm buttermilk biscuits or flaky croissants to round out the meal.

Creative Ways to Present

Want to impress guests? Serve individual portions in small ramekins or muffin tins for cute, single-serve portions. Alternatively, layer some avocado slices or a dollop of sour cream on top for added creaminess and flair. The possibilities are endless with this versatile Easy Overnight Breakfast Casserole Recipe.

Make Ahead and Storage

Storing Leftovers

Any leftovers from your casserole can be stored in an airtight container in the refrigerator for up to 3 days. Just be sure to cool the casserole completely before covering to preserve freshness and flavor.

Freezing

You can freeze individual slices wrapped tightly in plastic wrap and then foil for up to 2 months. This way, you always have a quick breakfast option ready to heat on busy mornings. Just thaw overnight in the fridge before reheating.

Reheating

To reheat, place leftovers in a preheated oven at 350°F (175°C) for 15-20 minutes or microwave for 1-2 minutes until warmed through. Reheating in the oven helps maintain that lovely crispy top and cozy texture.

FAQs

Can I use a different type of bread for this casserole?

Absolutely! Sturdy breads like challah, brioche, or French bread work wonderfully since they soak up the egg mixture without turning mushy. Just avoid super soft or pre-sliced sandwich bread, which might become too soggy.

Is it okay to skip the sausage for a vegetarian version?

Definitely. You can easily omit the sausage and add more veggies like mushrooms, bell peppers, or spinach. Consider adding some plant-based sausage or extra cheese for richness if desired.

How do I know when the casserole is fully cooked?

The casserole is done when the top is golden brown and the center is set, not jiggly. You can also use a toothpick inserted into the middle; it should come out clean or with just a few moist crumbs.

Can I prepare this casserole without refrigerating overnight?

While possible, the overnight soak gives the bread time to absorb the custard and enhances the flavors. If short on time, let it sit for at least 30 minutes before baking, but expect a slightly different texture.

What can I substitute for mustard powder?

If you don’t have mustard powder, a small amount of Dijon mustard or a pinch of turmeric can be used. Both add subtle complexity without overpowering the dish.

Final Thoughts

This Easy Overnight Breakfast Casserole Recipe is truly a lifesaver for busy mornings or special weekend gatherings. It’s simple to prepare, customizable to your tastes, and delivers big on flavor and comfort. Give it a try—you might find it becoming your go-to breakfast tradition that everyone loves waking up to.