Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish with cooking spray or butter.

In a skillet over medium heat, cook the breakfast sausage until browned and fully cooked, breaking it apart with a spoon as it cooks. Drain excess grease and set aside.

In a large bowl, combine the softened cream cheese, eggs, milk, garlic powder, onion powder, salt, and pepper. Whisk until smooth and well combined.

Add the cooked sausage and thawed hashbrowns to the egg mixture. Stir until everything is evenly coated.

Pour the mixture into the prepared baking dish and spread it out evenly.

Sprinkle the shredded cheddar cheese on top.

Bake in the preheated oven for 30-35 minutes, or until the casserole is set in the center and the cheese is bubbly and golden.

Let it cool for 5-10 minutes before slicing. Garnish with chopped chives if desired.