In a large oven-safe pan, combine the pasta, broccoli, milk, broth, garlic powder, salt, and pepper.
Stir everything together until well mixed.
Bring it to a simmer over medium heat, then cover and let cook for about 10 minutes.
Remove the lid and stir in 1 1/2 cups of cheese until melted and creamy.
Sprinkle the remaining cheese on top.