For the Cake, beat all ingredients in large bowl with electric mixer on low speed just until moistened, scraping side of bowl frequently. Beat on medium speed 2 minutes or until well blended
Pour into greased and floured 13x9-inch baking pan
Bake 30 to 35 minutes or until toothpick inserted in center comes out clean. Cool in pan on wire rack
Gradually beat in confectioners' sugar until smooth. Spread cake with Frosting