Overnight Breakfast Casserole

Imagine waking up to the savory aroma of cheese, eggs, and perfectly seasoned breakfast sausage wafting through your home. The Overnight Breakfast Casserole is the ultimate morning time-saver that doesn’t sacrifice flavor for convenience. This hearty, make-ahead dish combines fluffy eggs, golden bread cubes, melted cheese, and savory sausage into a morning masterpiece that bakes while you enjoy your first cup of coffee. You’ll learn how to prepare this crowd-pleasing breakfast the night before, allowing the flavors to meld together for a stress-free and delicious morning meal.

Why You’ll Love This Recipe

The Overnight Breakfast Casserole is the breakfast hero you’ve been searching for. First, the convenience factor is unmatched – prep it the night before, refrigerate, and simply bake it in the morning. This make-ahead breakfast casserole saves precious morning time while delivering restaurant-quality results.

The texture contrasts make this dish truly special. The top layer develops a perfectly golden, slightly crispy crust, while the interior remains soft and moist. Every bite offers a delightful combination of creamy eggs, chewy bread that’s soaked up all the savory flavors, melty cheese pockets, and hearty sausage pieces.

What makes this breakfast bake particularly wonderful is its adaptability. You can customize it with your favorite breakfast meats, cheeses, and vegetables, making it perfect for using leftovers creatively. It’s equally suited for feeding a hungry family on a busy weekday morning or impressing weekend brunch guests with minimal morning effort.

Ingredients

For this perfect Overnight Breakfast Casserole, you’ll need:

• 1 pound (450g) breakfast sausage, casings removed
• 1 medium onion, diced (about 1 cup)
• 1 red bell pepper, diced (about 1 cup)
• 2 cloves garlic, minced
• 6 cups day-old bread cubes (about 8-10 slices)
• 2 cups (8 oz/225g) shredded cheddar cheese
• 10 large eggs
• 2 cups (480ml) whole milk
• 1 teaspoon dried mustard powder
• 1 teaspoon salt
• 1/2 teaspoon black pepper
• 1/4 teaspoon paprika
• 2 tablespoons fresh chopped parsley (plus more for garnish)

Use day-old bread for the best texture – fresh bread can become too soggy. The mustard powder adds a subtle depth of flavor that complements the sausage perfectly. Feel free to use sharp cheddar for more pronounced cheese flavor or a milder cheddar for a more subtle taste.

Pro Tips

Bread Selection and Preparation
Choose the right bread for your make-ahead breakfast casserole. A sturdy bread like sourdough, French bread, or even brioche will hold up better than regular sandwich bread. Allow your bread to dry out slightly by cutting it into cubes and leaving it out for a few hours or lightly toasting it in the oven. This prevents the casserole from becoming overly soggy during the overnight rest.

Perfect Egg Mixture
For the creamiest texture in your Overnight Breakfast Casserole, whisk the eggs vigorously until they’re completely uniform with no streaks of whites visible. Then gradually incorporate the milk while continuing to whisk. This creates a silky-smooth custard base that will bake up beautifully. Adding a touch of heavy cream (replacing 1/4 cup of the milk) creates an even richer result.

Even Distribution of Ingredients
Layer your ingredients strategically for the best flavor in each bite. Start with half the bread cubes, then add half the sausage mixture and cheese. Repeat with remaining ingredients before pouring over the egg mixture. Instead of just pouring the egg mixture over the top, use a spatula to gently press down on the ingredients, ensuring the bread absorbs the egg mixture evenly. For the best flavor infusion, allow at least 8 hours (and up to 24 hours) of refrigeration time.

Instructions

Step 1: Prepare the Meat and Vegetables
In a large skillet over medium heat, cook the breakfast sausage, breaking it up with a wooden spoon until it’s no longer pink, about 5-7 minutes. Add the diced onions and bell peppers to the skillet with the sausage and sauté until softened, about 4-5 minutes. Add the minced garlic and cook for an additional 30 seconds until fragrant. Remove from heat and let the mixture cool slightly while you prepare the other ingredients.

Step 2: Prepare the Baking Dish and Bread
Grease a 9×13-inch baking dish with butter or cooking spray. If your bread isn’t already dry or day-old, spread the bread cubes on a baking sheet and place in a 300°F (150°C) oven for about 10 minutes to dry out slightly. Arrange half of the bread cubes in an even layer in the prepared baking dish.

Step 3: Layer the Casserole
Sprinkle half of the sausage mixture over the bread layer, followed by half of the shredded cheese. Repeat with another layer of the remaining bread cubes, sausage mixture, and cheese. This layering technique ensures that every serving has a perfect balance of ingredients.

Step 4: Prepare the Egg Mixture
In a large bowl, whisk together the eggs, milk, dried mustard powder, salt, black pepper, paprika, and chopped parsley until well combined. Carefully pour this mixture evenly over the layered ingredients in the baking dish. Using the back of a spatula, gently press down on the top layer to help the bread absorb the egg mixture.

Step 5: Refrigerate Overnight
Cover the baking dish tightly with plastic wrap or aluminum foil and refrigerate for at least 8 hours or overnight (up to 24 hours). This resting period is crucial for the Overnight Breakfast Casserole as it allows the bread to fully absorb the egg mixture and the flavors to meld together beautifully.

Step 6: Bake the Casserole
When you’re ready to bake, remove the casserole from the refrigerator and let it sit at room temperature for about 30 minutes while you preheat the oven to 350°F (175°C). Remove the cover and bake for 45-55 minutes, or until the casserole is puffed, golden brown on top, and the center is set (it shouldn’t jiggle when you gently shake the dish).

Step 7: Serve
Let the casserole rest for 5-10 minutes before serving. This allows it to set and makes it easier to cut into neat portions. Garnish with additional fresh parsley if desired, and serve warm.

Variations

Vegetarian Breakfast Casserole
Create a meatless version of this Overnight Breakfast Casserole by replacing the sausage with sautéed mushrooms (about 8 oz/225g) and adding 1 cup of baby spinach. For additional protein, incorporate 1 cup of black beans or chickpeas. The earthiness of mushrooms pairs wonderfully with the eggs and cheese, while the spinach adds color and nutrients. This vegetarian option is equally satisfying and protein-rich.

Southwest Breakfast Casserole
Transform this into a southwest-inspired dish by using Mexican chorizo instead of breakfast sausage. Add 1 diced jalapeño (seeds removed for less heat), 1 cup of corn kernels, and replace the cheddar with a Mexican cheese blend or pepper jack. Season the egg mixture with 1 teaspoon of cumin and 1/2 teaspoon of chili powder. Serve with sliced avocado, salsa, and sour cream for a delicious twist on your morning breakfast bake.

Mediterranean-Style Casserole
For a Mediterranean flavor profile, substitute Italian sausage for the breakfast sausage and add 1/2 cup chopped sun-dried tomatoes, 1/2 cup pitted and sliced Kalamata olives, and 1 tablespoon of dried Italian herbs. Replace the cheddar with 1 cup of crumbled feta and 1 cup of mozzarella. This variation brings bright, tangy flavors to your breakfast table.

Storage and Serving

Once your Overnight Breakfast Casserole has cooled completely, cover any leftovers tightly with plastic wrap or transfer portions to airtight containers. Refrigerated leftovers will stay fresh for up to 4 days. For longer storage, cut the casserole into individual portions, wrap each piece in plastic wrap and aluminum foil, and freeze for up to 2 months. Reheat refrigerated portions in the microwave for 1-2 minutes or in a 350°F (175°C) oven for 10-15 minutes until warmed through.

For elegant serving, pair slices of this breakfast casserole with a simple arugula salad dressed with lemon and olive oil for a brunch-worthy presentation. Add a side of roasted breakfast potatoes and fresh fruit for a complete breakfast spread that will impress guests. For a casual family breakfast, serve with toast and preserves or a simple yogurt parfait for a balanced morning meal.

For an extra special touch, offer a selection of toppings like sliced avocado, hot sauce, fresh salsa, or herb-infused sour cream to allow everyone to customize their portion.

FAQs

Can I assemble this casserole more than one day in advance?
Yes, you can prepare this Overnight Breakfast Casserole up to 2 days before baking. Just ensure it’s tightly covered in the refrigerator. The bread may absorb more of the egg mixture, resulting in a slightly different texture, but the flavor will be delicious.

What’s the best way to tell if the casserole is fully cooked?
The casserole is done when the center is set and doesn’t jiggle when gently shaken. An instant-read thermometer inserted in the center should read 160°F (71°C). The top should be golden brown and slightly puffed.

Can I use a different type of meat?
Absolutely! Cooked and crumbled bacon, diced ham, or even shredded chicken can substitute for the sausage. Just ensure any raw meat is fully cooked before adding it to the casserole.

My casserole seems too dry/too wet. What went wrong?
If too dry, your bread may have been too dry initially or the casserole baked too long. If too wet, it may need additional baking time, or your bread was too fresh and didn’t absorb enough liquid.

Can I make this casserole dairy-free?
Yes, substitute the milk with unsweetened almond, soy, or oat milk, and use your favorite dairy-free cheese alternative. The texture will be slightly different but still delicious.

Conclusion

This Overnight Breakfast Casserole is comfort food at its finest — a warm, satisfying blend of savory flavors that transforms ordinary breakfast ingredients into something truly special. It’s the kind of dish that brings everyone to the table with eager anticipation, whether for a holiday morning, weekend brunch, or making an ordinary weekday feel special. The beauty of this make-ahead marvel is that it gives you the gift of time while still delivering homemade goodness. From customizing it with your favorite ingredients to enjoying stress-free mornings, this casserole proves that planning ahead can result in some of the most memorable meals shared around your table.

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