Three-Cheese Macaroni

Make the cheese sauce

Bring a large pot of water to a boil. In a small saucepan over medium heat, warm the milk until small bubbles begin to form around the edge of the pan. Remove from the heat. In a large saucepan over low heat, melt the butter. Add the flour, whisking to incorporate. Raise the heat to medium-low and cook the mixture, whisking constantly