limp in a skillet coated with no-stick cooking spray. Meanwhile, tear the cheese slices into small bits and place them in a measuring cup with the milk. Melt on a stove in a saucepan, stirring twice. Layer the roast beef on the roll, followed by the onion and the cheese sauce. Wrap in foil and warm in a 350-degree oven for several minutes. Contain 7 grams fat.