Heat 1 cup milk 2 minutes on medium high. Set aside. Melt 2 tablespoons butter on high. Stir in 2 tablespoons flour, heat 1 minutes more on high. Briskly stir in warm milk. Blend well. Cook on high 2 1/2 minutes, or until boiling. Stir in 1 cup grated cheddar cheese. Blend well.