Preheat Oven:
Preheat oven to 350°F (175°C). Grease a 9×13-inch baking dish.

Prepare Sausage and Veggies:
Cook breakfast sausage in a skillet until browned and cooked through. Remove and drain excess fat. In the same skillet, sauté onions and bell peppers until softened.

Mix Eggs and Seasonings:
In a large bowl, whisk together eggs, milk, garlic powder, salt, and pepper.

Assemble Casserole:
Spread thawed hashbrowns evenly in the baking dish. Layer cooked sausage, onions, and bell peppers on top. Pour egg mixture over everything. Sprinkle shredded cheddar cheese on top.

Bake:
Bake uncovered for 40–45 minutes or until eggs are fully set and cheese is melted and bubbly.

Serve:
Let cool slightly before slicing. Perfect for a hearty breakfast or brunch!