 Marbling the cake is a fun way to blend two flavors into one beautiful sweet tree. Your batters will need to contrast in color for the full effect using vanilla and chocolate batters works really nicely. Start by scooping the batter into a prepared pan alternating between the two batters creating a checkerboard effect. Repeat with a second layer being sure to place the dark batter on top of the other layers light batter and vice versa. A table knife works best for swirling the batters together by creating a nice even swirl. Take the end of your knife and place it in the batter almost to the bottom of the pan. Start swirling the batters from one end of the pan to the other in a large zigzag motion. Remove and wipe the excess batter from the end of the knife. Turn the pan one quarter turn and repeat the swirling motion in the opposite direction. Resist the urge to swirl the batters anymore as this will result in a muddy looking overblended cake. Bake the cake according to recipe directions and then marvel at the marvel effect you've just created.