The Ultimate Overnight Breakfast Casserole

Mornings have never been easier or more delicious with the Ultimate Overnight Breakfast Casserole. Combining savory breakfast sausage, crispy hash browns, fluffy eggs, creamy sour cream, and gooey cheddar cheese, this casserole is the ultimate comfort breakfast that feeds a crowd. The best part? You assemble it the night before, refrigerate, and bake in the morning for a stress-free, hearty breakfast.

This casserole is perfect for busy weekdays, weekend brunches, or feeding family and friends. The hash browns provide a tender, slightly crispy base, while the sausage adds savory depth. The eggs and sour cream create a creamy custard that binds the casserole together, and the cheddar cheese adds that irresistible melty topping. Chopped green onions finish it off with a fresh, mild flavor and a pop of color.

Whether you’re a seasoned cook or new to breakfast casseroles, this recipe is forgiving, customizable, and full of flavor. It’s a breakfast you’ll crave again and again.

Ingredients

• 1 pound breakfast sausage
• 1 package frozen hash browns (about 30 oz)
• 8 large eggs
• 1 cup milk
• 1 cup sour cream
• 2 cups shredded cheddar cheese
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1/4 cup chopped green onions

Optional add-ins: diced bell peppers, mushrooms, or cooked bacon for extra flavor

Preparation Method

Preparing the Sausage

Preheat your oven to 350°F (175°C). In a large skillet over medium heat, cook the breakfast sausage until fully browned, breaking it apart with a spatula. Drain any excess grease and set aside.

Preparing the Hash Browns

If your frozen hash browns are in large clumps, break them up slightly. Spread them evenly in a greased 9×13-inch baking dish to form the base layer of your casserole.

Preparing the Egg Mixture

In a large bowl, whisk together the eggs, milk, sour cream, salt, and black pepper until smooth. This creamy mixture will soak into the hash browns, creating a custardy texture.

Assembling the Casserole

Layer the cooked sausage evenly over the hash browns. Sprinkle 1 1/2 cups of shredded cheddar cheese over the sausage. Pour the egg and sour cream mixture evenly over all layers. Gently press with a spatula to ensure the eggs soak into the hash browns. Sprinkle the remaining 1/2 cup cheddar cheese on top, followed by the chopped green onions.

Refrigerating Overnight

Cover the baking dish tightly with plastic wrap or aluminum foil and refrigerate overnight. This allows the flavors to meld and the hash browns to absorb the custard mixture fully.

Baking the Casserole

Remove the casserole from the refrigerator and let it sit at room temperature for 10-15 minutes. Bake uncovered in the preheated oven for 50-60 minutes, or until the top is golden brown and the eggs are fully set. A knife inserted into the center should come out clean.

Serving the Casserole

Allow the casserole to cool for 5-10 minutes before slicing. Serve warm for a satisfying breakfast or brunch. This dish pairs well with fresh fruit, salsa, or a side of toast for a complete morning meal.

Tips for Perfect Overnight Breakfast Casserole

1. Use day-old or thawed hash browns: They absorb the custard better and prevent excess moisture.
2. Customize with vegetables: Bell peppers, mushrooms, or spinach make the casserole even more flavorful.
3. Cheese variations: Cheddar is classic, but Swiss, Monterey Jack, or a cheese blend works well.
4. Make-ahead convenience: Assemble the casserole the night before for an effortless morning.
5. Check for doneness: Insert a knife in the center; it should come out clean when fully baked.

Frequently Asked Questions

Can I use cooked bacon instead of sausage?
Yes! Bacon adds a smoky flavor. Adjust the quantity based on preference.

Can I make this casserole vegetarian?
Yes, substitute the sausage with plant-based sausage or roasted vegetables.

Can I freeze the casserole?
Yes, assemble and freeze before baking for up to 2 months. Thaw overnight in the refrigerator and bake as directed.

Can I use different cheese?
Absolutely! Cheddar works best, but Swiss, Monterey Jack, or a mix of cheeses will taste delicious.

Can I add extra vegetables?
Yes, diced bell peppers, mushrooms, or spinach can be layered in for added nutrition and flavor.

Print

This Ultimate Overnight Breakfast Casserole is a crowd-pleasing, savory, and indulgent breakfast that’s easy to make ahead and perfect for any morning. With tender hash browns, savory sausage, creamy eggs, and melty cheddar cheese, it’s a breakfast you’ll want to enjoy again and again.