My son can't decide between chocolate or yellow cake for his birthday and since it's his 16th, I said I'd do both. I want to bake one layer of choc. cake, one layer of yelllow cake, split each, and alternate to make a four-layer cake with coconut filling (his favorite). Here's my question: instead of baking two separate batches of cake and ending up with two extra layers (since I only need one layer of each), is there any reason I can't make a standard yellow cake recipe, bake half like it is and add some melted unsweetened or bittersweet choc to the rest of the batter before baking? That way I only end up with one layer of each flavor and presumably they'd be pretty close in texture. Any obvious reason this won't work? Is there anything else I have to add in addition to the melted chocolate?