A crumble is a baked dessert of softened fruit under a rough, buttery topping made by rubbing flour, fat, and sugar together into coarse crumbs. As it bakes, the fruit releases its juices and turns jammy while the topping sets into a crisp, golden, uneven crust — the textural contrast between bubbling fruit and crunchy streusel is the signature of the dish. Apple is the classic filling, often mixed with blackberry, rhubarb, plum, or gooseberry for acidity, with sugar and spice adjusted to the tartness of the fruit. Served hot with custard, cream, or ice cream, the crumble is one of the simplest fruit desserts in British and American home cooking. It also scales easily for foodservice, where the same ratio of fruit to topping works from a single ramekin to a full tray.