A crumble is a casserole filled with some manner of stewed or baked fruit, topped with a crispy layer made from flour, sugar, and butter, usually with the addition of other grains or nuts. It is baked in a casserole, and often served with ice cream.
Crumble and crisp are two words for the same thing, though crumble seems to be the more common term in the UK, while crisp is more common in North America. As usual, Canadians comfortably elide the British and American vernaculars.
Crumble should not to be confused with cobbler, which is a similar dish from the American south. Like a crumble, cobbler is made with stewed fruit, but the topping takes the form of a worked dough, such as biscuit.
As the name implies, crumbles should have a coarse, irregular texture, and they should taste like butter and grain. My preferred ingredients are whole wheat flour, dark brown sugar, butter, rolled oats, and possibly some cold-pressed canola to boost the grass-grain flavour. Salt is also important.
You can replace all or part of the rolled oats in the ratio below with any number of substitutes. Nuts are welcome, especially walnuts. If you have biscuits that are a couple days old and too hard to enjoy on their own, you can bust them up. Even bread crumbs work well.
There are a couple essential, crazy-important details to which you must absolutely adhere when making crumble topping: the butter must be very, very cold, and it must be cut into the other ingredients until it is the proper size. Fridge temperature at the very warmest. The idea is to bust the cold butter into pea-sized pieces distributed through the flour and grain. If the butter is too warm it will not stay as the little pebbles that makes crumble crumbly. If you bust the butter too fine, it the topping will be a flat mat on top of the fruit. Actually I have a picture of such an ill-prepared crumble:
Now compare that to the beautiful, rocky surface of a crumble made with properly chilled butter. See the difference?
As for the fruit. My crumble fillings are identical to my pie fillings: a good balance of sweet and tart, and firm enough to cut and serve without running all over the diner’s plate, but not so firm as to be gummy on the tongue. In fact I typically only make crumbles after I have made pie, and I have leftover filling but no pastry to stuff it into. Then I simply pour the fruit into ramekins or a small casserole, and top with the crumble mix elucidated below.
Ingredients (by weight)
- 2 part whole wheat flour
- 2 part dark brown sugar
- 3 parts very cold, unsalted butter
- 2 part rolled oats
- Pulse the flour, sugar, butter, and salt in a food processor until the butter has broken into irregular pieces roughly the size of peas. The crumble should cycle well in the food processor; if the mixture starts to mat and stick to the sides of the bowl, the butter is too warm.
- Remove the mixture from the processor and stir in the rolled oats.
- Crumble onto chilled stewed fruit. Bake at 375°F until the crumble is golden brown and the fruit is gently bubbling.