Peanut Butter Frosting
["5 Tbsp. milk", "1/4 c. peanut butter", "2 Tbsp. butter or margarine", "1/4 tsp. salt", "1/2 tsp. vanilla", "4 c. (1 lb.) unsifted powdered sugar"]
["Stir together in saucepan over low heat the milk, peanut butter and butter until well blended. Remove from heat. Add salt and vanilla. Gradually stir in sugar; beat until smooth and creamy. If too stiff to spread easily, beat in few drops of milk. Frosts tops and sides of two 8 or 9-inch layers."]
["milk", "peanut butter", "butter", "salt", "vanilla", "powdered sugar"]