Preheat oven to 350°. Grease and lightly flour two 9-inch round cake pans*; set aside.
Beat all ingredients in large bowl with electric mixer on low speed 30 seconds. Beat on medium speed, scraping sides occasionally, 2 minutes. Pour batter into prepared pans.
Bake 30 minutes or until toothpick inserted in centers comes out clean. Cool 10 minutes on wire rack; remove from pans and cool completely.
Beat marshmallow creme, peanut butter and Spread in small bowl with electric mixer at low speed until smooth. Increase speed to medium and beat in remaining ingredients until blended. Evenly spread frosting** on completely cooled cake.
*If desired, prepare 13 x 9-inch layer cake or 24 cupcakes.
**Frosting will be sticky. Be sure cake is completely cooled.