Unmold - to remove food from its container, usually a decorative mold. Gelatin and fatty dishes can be unmolded by setting briefly in hot water, then reversing over the serving dish.
Unsweetened chocolate - chocolate liquor or mass, without added sugar or flavorings; used in baking.
Upside-Down Cake - a cake with fruit placed on the bottom of the pan, topped by batter. After baking, the cake is turned upside down and served with the fruit on top.