Step 3
Meanwhile, melt butter in medium saucepan on medium heat. Whisk in flour; cook and stir 2 min. Gradually whisk in milk; cook and stir 3 to 5 min. or until thickened. Add cheeses and nutmeg; mix well. Cook 1 to 2 min. or until cheddar is completely melted and sauce is well blended, stirring constantly.