Heat oven to 325 F. Grease bottom and sides of three 8-inch round cake pans with shortening and lightly flour, or spray with baking spray with flour. In a large bowl, beat all cake ingredients with electric mixer on low speed about 30 seconds or until moistened. Beat on medium speed 2 miuntes, scraping bowl occasionally. Divide batter evenly among pans. Bake for 23 to 28 minutes or until top springs back when lightly touched in center. Cool 15 minutes. Remove from pans; cool completely. In a large microwaveable bowl, microwave marshmallow creme uncovered on HIGH 15 to 20 seconds to soften. Add butter. Beat with electric mixer on medium speed until smooth. Beat in powdered sugar and salt beat until smooth. Spread between layers and over top and sides of a cake.