Using a roux can help to create a creamy, smooth texture in the cheese sauce and can help to prevent the sauce from becoming lumpy or grainy. However, some recipes use other thickening agents, such as cornstarch or arrowroot powder, or rely on the cheese itself to thicken the sauce.u003cbr/u003eu003cbr/u003eIf you prefer a lighter mac and cheese without a roux, you can make a simple cheese sauce by combining milk, cheese, and any other desired flavorings (such as garlic or mustard) and whisking them together over low heat until the cheese is melted and the sauce is smooth.