Preheat oven to 350 F. Cook pasta according to package directions, drain and place into a large bowl. Melt butter in a large saucepan and cook garlic until fragrant.
Add in flour, cook for a minute to brown. Add in milk, 1 1/2 cups cheese, salt, and pepper. Cook over medium heat, stirring constantly until the cheese has fully melted and the sauce has thickened.
Mix sauce with pasta, spread mixture out into a greased baking dish. Top with the remaining 1 1/2 cups cheese. Cook stuffing mix according to package directions. Top the prepared stuffing mix on the mac and cheese. Bake for 25-30 minutes.
