Rocky Road Frosting
["2 (1 oz.) sq. unsweetened chocolate", "2 c. miniature marshmallows", "1/4 c. water", "4 Tbsp. margarine", "21/2 c. powdered sugar", "1 tsp. vanilla", "1/4 c. chopped walnuts"]
["In a 2-quart heavy saucepan, combine chocolate, half the marshmallows, water and butter.", "Heat until blended, stirring constantly.", "Cool slightly; add sugar and vanilla.", "Beat until thick.", "Stir in remaining marshmallows.", "Add nuts.", "Frosts one 13 x 9-inch cake."]
["unsweetened chocolate", "marshmallows", "water", "margarine", "powdered sugar", "vanilla", "walnuts"]