Homemade Mac and Cheese

Name: Homemade Mac and Cheese
Ingredients: 1 pound dried elbow macaroni; 6 tablespoons (3/4 stick) unsalted butter, plus more for the baking dish; 1 1/2 pounds medium cheddar cheese (about 6 cups shredded); 1/4 cup all-purpose flour; 5 cups whole milk or half-and-half, or a combination; 1 3/4 teaspoons kosher salt; 1/4 teaspoon freshly ground black pepper; Paprika, for garnish (optional)