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Cheesy Sausage Breakfast Casserole Squares

When you want a hearty breakfast that can feed a crowd without requiring a lot of last-minute cooking, Cheesy Sausage Breakfast Casserole Squares are a delicious choice. This comforting casserole combines savory sausage, fluffy eggs, melty cheese, and a tender, satisfying base that bakes into neat squares.

The best part is its versatility. It works beautifully for a relaxed weekend breakfast, holiday brunch, family gatherings, or even a make-ahead weekday meal. Once baked and slightly cooled, the casserole can be cut into squares, making it easy to serve and enjoy.

Why You’ll Love This Breakfast Casserole

This recipe brings together several classic breakfast flavors in one simple dish. The sausage provides a savory, seasoned bite, while the eggs create a soft and fluffy center. Plenty of melted cheese ties everything together and gives the casserole its rich, comforting character.

Another advantage is that the casserole can be prepared ahead of time. You can assemble much of it before breakfast, refrigerate it, and bake it when you’re ready.

Ingredients

For the casserole squares, you’ll need:

1 pound breakfast sausage
8 large eggs
2 cups shredded cheddar cheese
1 cup shredded Monterey Jack cheese
1 cup whole milk
1/2 cup sour cream
1 teaspoon Dijon mustard
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/2 teaspoon salt
1/4 teaspoon black pepper
4 cups cubed or torn bread
1 tablespoon butter or cooking spray for the baking dish
2 tablespoons chopped fresh parsley, optional

You can use mild or spicy breakfast sausage depending on your preference. Cheddar gives the casserole a familiar sharp cheese flavor, while Monterey Jack melts especially well.

Step-by-Step Method

Step 1: Prepare the Baking Dish

Preheat your oven to 350°F (175°C).

Lightly grease a 9 × 13-inch baking dish with butter or cooking spray. Greasing the dish helps prevent the casserole from sticking and makes it easier to cut and remove the squares after baking.

Set the prepared dish aside while you prepare the filling.

Step 2: Brown the Sausage

Place a large skillet over medium heat and add the breakfast sausage.

Cook for about 6–8 minutes, breaking it apart with a wooden spoon or spatula as it cooks. Continue until the sausage is browned and fully cooked.

If there is a large amount of excess grease in the skillet, carefully drain it.

Set the cooked sausage aside to cool slightly.

Step 3: Prepare the Egg Mixture

Crack the eggs into a large mixing bowl.

Add the milk, sour cream, Dijon mustard, garlic powder, onion powder, salt, and black pepper.

Whisk everything together until the mixture is smooth and well combined.

The sour cream adds richness and helps keep the baked eggs tender, while the mustard gives the casserole a subtle savory depth without making it taste strongly of mustard.