Preheat your oven to 375 degrees Fahrenheit. Grease a 9x13 inch baking dish generously.

In a large skillet over medium-high heat, cook the ground sausage until browned and crumbled. Drain excess grease.

In a large mixing bowl, whisk together the eggs, milk, onion powder, garlic powder, salt, and pepper until smooth.

Spread the thawed hashbrowns evenly in the bottom of the prepared baking dish. Layer the cooked sausage over the potatoes, followed by 1 cup of shredded cheddar cheese.

Pour the egg mixture over the entire dish, ensuring it reaches every corner. Top with the remaining cup of cheese.

Cover with aluminum foil and bake for about 40 minutes. Remove the foil and bake for an additional 15 to 20 minutes until golden brown and firm in the center.

Let the casserole rest for 10 minutes before slicing.