Meanwhile, in 2-quart saucepan, melt butter over medium heat. Cook mushrooms in butter just until tender; remove from saucepan with slotted spoon and set aside. Stir flour, salt and pepper into same saucepan. Gradually stir in broth until mixture is smooth; stir in half-and-half. Heat to boiling, stirring constantly. Boil and stir 1 minute.