Grease 9x13 inch pan. In small saucepan, combine all filling ingredients except vanilla; cook over low heat, stirring constantly, until melted. Stir in vanilla; set aside. In large saucepan, combine marshmallows, peanut butter, margarine and corn syrup; cook over low heat, stirring occasionally, until melted. Remove from heat. Add cereal; stir until well coated. With metal spatula, spread half of cereal in greased pan. Spread filling over cereal mixture. Press remaining cereal mixture over top. Refrigerate at least 10 minutes. Cut into bars. ----