I have been asked to make a marble cake in a few weeks and I have some questions. I normally use a doctored box mix but have been experimenting with scratch receipes. My question is, how do you make a marble cake from scratch. Do have to make two separt batters or can i add something to a portion of my reg. white cake recipe? I have "The Cake Bible" and it has the "Checkerboard Fantacy Cake" that you just add melted semi-sweet chocolate to half the batter. Will that work for any recipe?