01 -
Preheat oven to 350°F (175°C). Grease a deep 8x8-inch square baking pan and evenly layer thawed hash brown potatoes inside.
02 -
In a large skillet over medium heat, cook and crumble beef sausage with diced onion until browned, about 10 minutes. Drain excess fat.
03 -
Whisk eggs, milk, onion powder, garlic powder, salt, and black pepper in a large bowl until fully combined.
04 -
Pour egg mixture over the hash browns. Sprinkle half of the shredded Cheddar cheese on top. Layer sausage mixture evenly, then add remaining Cheddar cheese. Cover pan tightly with aluminum foil.
05 -
Bake in preheated oven for 1 hour.
06 -
Remove foil and continue baking until a knife inserted into the center comes out clean, approximately 10 minutes.
07 -
Allow casserole to stand for 5 minutes before serving to set.