Why You’ll Love Brunch Casserole Recipe

I love this recipe because I can prepare it ahead of time and enjoy a relaxed morning while it bakes. I like how it feeds a crowd effortlessly, develops even better flavor after resting overnight, and fills the kitchen with a warm, inviting aroma. It’s reliable, filling, and always a favorite at the table.

Ingredients

(Note: All ingredient amounts are listed in the recipe card below.)

1 lb beef breakfast sausage
2 medium onions, chopped
2 cups sliced fresh mushrooms
1 tbsp butter
4 cups frozen hash browns, thawed
1 tsp salt
½ tsp black pepper
¼ tsp garlic salt
4 eggs
1½ cups milk
Pinch of dried parsley
1 cup shredded cheddar cheese

Directions

I start by cooking the sausage in a large skillet over medium heat until fully cooked and lightly browned. I transfer it to a plate and set it aside.

In the same skillet, I melt the butter and sauté the chopped onions and mushrooms for about 6–8 minutes, until soft and lightly golden.

In a large bowl, I combine the thawed hash browns, cooked sausage, and sautéed vegetables. I sprinkle in the salt, black pepper, and garlic salt, then mix everything together until evenly combined. I press this mixture into a greased 9×13-inch baking dish.

In another bowl, I whisk the eggs with the milk and dried parsley until smooth. I pour this mixture evenly over the hash brown base, gently pressing down so the liquid spreads throughout. I finish by sprinkling the shredded cheddar cheese evenly on top.

I cover the dish tightly and refrigerate it for at least 8 hours or overnight. When ready to bake, I preheat the oven to 350°F (175°C), uncover the casserole, and bake for about 1 hour and 15 minutes until the top is golden, bubbly, and the center is fully set. I let it rest for 10–15 minutes before slicing.

Servings and Timing

I usually cut this casserole into 8 generous servings. Prep time takes me about 25 minutes, chilling time is at least 8 hours, and baking time is around 1 hour and 15 minutes, making it ideal for an easy, well-planned brunch.

Variations

When I want to change things up, I add bell peppers, spinach, or roasted red peppers for extra color and flavor. I sometimes swap cheddar for Monterey Jack, Colby, or Gruyère, or add a pinch of paprika or onion powder to deepen the seasoning.

Storage/Reheating

I store leftovers covered in the refrigerator for up to 3 days. To reheat, I warm individual portions in the microwave or reheat the entire dish covered in a 325°F oven until heated through. I avoid overheating so the casserole stays creamy.

FAQs

Can I make this casserole ahead of time?

I assemble it the night before and bake it fresh the next day with great results.

Do the hash browns need to be thawed?

I always thaw them to prevent excess moisture and uneven cooking.

How do I know when it’s fully cooked?

I look for a golden top and a firm center with no jiggle.

Can I use a different baking dish size?

I stick with a 9×13-inch dish to ensure even baking.

Can I add more cheese?

I often add an extra half cup when I want it extra cheesy.

Is this casserole good for a crowd?

I find it’s perfect for groups because it slices cleanly and serves easily.

Can I leave out the mushrooms?

I simply omit them or replace them with bell peppers or zucchini.

Why should it rest before slicing?

Resting helps the egg custard set so the slices hold their shape.

Can I double the recipe?

I double it by using two separate baking dishes rather than one deep dish.

What pairs well with this casserole?

I like serving it with fresh fruit, a simple salad, or warm bread.

Conclusion

This brunch casserole is one of those dependable recipes I come back to again and again. I love how it delivers comfort, flavor, and ease all in one dish, making it perfect for relaxed mornings and shared meals around the table.