Preheat oven to 350 degrees F. Grease and flour a 13 x 9 pan OR 2- 8 inch round cake pans. In a large mixing bowl, combine all the cake ingredients until throughly mixed. Pour batter into prepared pan(s); bake 30 - 35 minutes. Cake will be real moist. Cool in pan 15 minutes, then invert to wire rack; cool completely.
Frosting: Cream butter and cream cheese til light and fluffy. Add zest and juice stir throughly. Add confectioner's sugar one cup at a time. Scrape sides of bowl after each addtion. Frost cake.