Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish with butter.

In a large skillet over medium heat, cook the sausage thoroughly until browned, about 7-10 minutes. Drain excess fat.

Reduce heat to low and stir in cream cheese until melted and combined with the sausage, about 2-3 minutes.

Spread thawed hashbrowns evenly in the greased baking dish. Drizzle melted butter over the top and season with salt and pepper.

Layer the creamy sausage and cream cheese mixture over the hashbrowns, pressing down gently.

In a separate bowl, whisk together eggs, milk or half-and-half, and seasonings.

Pour the egg mixture evenly over the layered sausage and hashbrowns, ensuring even coverage.

Sprinkle shredded cheddar cheese over the casserole and bake uncovered for 40-45 minutes until the eggs are set.

Let the casserole cool for 5-10 minutes before garnishing with chopped green onions or parsley and serving.