1. Preheat oven to 375°F (190°C). Cook the pasta according to package instructions until al dente. Drain and set aside.
2. In a saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute to create a roux.
3. Gradually whisk in milk, stirring constantly until the sauce thickens. Add garlic powder, salt, and pepper.
4. Stir in 1 1/2 cups of mozzarella and 1/2 cup of Parmesan cheese until melted and creamy.
5. Combine the cooked pasta with the cheese sauce, mixing well. Transfer to a baking dish.
6. Sprinkle the remaining mozzarella and Parmesan on top. Bake for 20-25 minutes, or until bubbly and golden brown.
7. Garnish with fresh parsley and serve hot.