There is a Sunday in September when the hedgerows along the lane have gone heavy with blackberries, and you come home with a carrier bag, a stained thumb, and a couple of thorn scratches up your forearm. That bag on the kitchen table is the whole reason for this pudding. Everything else, the apples, the butter, the flour, the oats, is already in the house.

Bramleys are the apple for this. I won't be talked out of it. They collapse in the oven into something soft and tart, almost savoury, which is what the blackberries need to push against. A dessert apple stays firm and polite, and this is not a polite pudding. The fruit should slump. The juice should run dark and purple. The crumble on top should be thick and uneven, sandy in places and bouldery in others, with the demerara catching on the peaks and going to toffee.

I wrote it down in the notebook years ago, after the first proper blackberrying walk of a new autumn: "Bramley, bramble, oats, cream. Enough." It's still enough. A recipe is a conversation, not a contract, and this one has been going on between me and September for a long time.

Serve it warm, not hot. Cold cream poured from a jug so it pools against the hot fruit and melts slowly at the edges. There are few better feelings than carrying a crumble to the table, the dish still bubbling faintly at the rim, and spooning it out into bowls for people who've had a long walk and are ready to sit down. We're only making dinner. This is how you end one.