Vanilla Sponge Cake, Chiffon Cake Recipe, Simple Cake Recipe
Heat a large waffle sponge cake in microwave oven only. Some stores that specialize in cakemaking and other confectionery carry it, and there are some online sources, such as the King Arthur Flour website, as well as this source and this one. Melt the butter over hot water or in the microwave.
Try my Sponge Cake in a Mug and almost Mug Meal recipes! I have to say the only thing more satisfying than cake, is cake cooked in.