Don't tell the secret ingredient, that is. Not until everybody has asked for seconds. And even then I'd think about it twice if I were you. Call it spice cake...that would work. Plum cake. Dried plum cake. Dried plums as in prunes, the much maligned cousins of raisins. Please don't let the fact that it is a prune cake stop you from making it. The cake is spicy and moist, and the glaze is good enough to eat all by itself. And there are no ill effects from eating this prune cake. I promise.