Foolproof Peanut Butter Fudge 1 tub (1 lb) Vanilla Frosting 1 jar (16.3 oz) Creamy Peanut Butter Line a 9 x 9 inch dish with foil and set aside. In a microwave safe bowl, add Vanilla Frosting and Peanut Butter, do not stir. Microwave 1 minute. Stir until combined and smooth. Pour into pan and spread until even. Refrigerate until firm. Remove fudge from the pan using foil and cut into squares.