Zebra (Marble) Cake

A marble cake in which vanilla and then chocolate batters are slowly and alternately added to the baking dish. If you do it right, in the end, it should resemble zebra stripes! If not, it's okay, it'll taste good, anyway. I substituted ground hazelnuts in place of a half-cup of the flour. Recipe from Lauren Chattman's Cake Keeper Cakes.