Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish to prevent sticking.
Cook the turkey sausage: In a large skillet over medium heat, crumble and cook the turkey sausage until it’s browned and cooked through, about 6-8 minutes. Drain excess fat if needed and set aside.
Mix the creamy base: In a large bowl, whisk together the softened cream cheese and milk until smooth. Add the eggs, garlic powder, onion powder, salt, and pepper. Whisk again until everything is well combined.
Add the hashbrowns and cheese: Stir the thawed hashbrowns, cooked sausage, and shredded cheddar cheese into the creamy egg mixture. Make sure everything is evenly incorporated.
Transfer to the baking dish: Pour the mixture into your prepared baking dish and spread it out evenly.
Bake: Place the casserole in the oven and bake for 45-50 minutes, or until the top is golden brown and the casserole is set in the middle. A knife inserted in the center should come out clean.
Optional garnish: Remove from the oven and sprinkle chopped green onions on top for a fresh, vibrant finish.
Let it cool slightly before serving to allow the casserole to set and make it easier to slice.