Meanwhile, to make dipping sauce, in 2-quart saucepan, melt remaining 2 tablespoons butter over medium heat. Stir in flour with wire whisk. Cook 2 minutes, stirring constantly. Stir in soup with wire whisk. Bring to a boil over medium-high heat, stirring constantly. Reduce to simmer; cook until thickened, about 10 minutes, stirring occasionally.