Heat oven to 350 degrees. Grease bottom and side of an 8 or 9 in round pan with shortening, lightly flour.
Beat all ingredients except whipped topping in large bowl with mixer on low speed 30 seconds, scraping bowl constantly. Beat on high speed for 2 minutes, scraping bowl occasionally. Pour into pan.
Bake 30-35 minutes or until toothpick comes out clean. Cool 10 minutes, remove from pan to wire rack. Cool completely, about 1 hour 30 minutes.
Cut cake horizontally to make 2 layers. Mark sides of cake with toothpicks, and cut with long thin serrated knife. Spread about 1/2 of the whipped topping over bottom of cake. Add top of cake. Top with remaining whipped topping. Refrigerate.