Every chestnut gets a cut before it goes in the oven

Sweet chestnuts turn up at our market as winter gets close — glossy and dark brown, as if someone had polished each one. I buy a small bag, just enough for one evening with tea for the whole family. The first time, like plenty of people, I put them in the oven whole. Ten minutes later there was a bang, then another, and the inside of the oven door was covered in shell.

A chestnut is full of moisture. In the heat it turns to steam, the tight shell has nowhere to let it out, and so it bursts. Now every chestnut gets a cut. I lay it flat side down on the board, hold it steady with my fingertips and, with a small sharp knife, cut a cross or one long slit across the rounded side — through the shell, but not deep into the nut. I keep the blade moving away from me; chestnuts are slippery.

Then onto a tray in a hot oven for about twenty minutes, until the cuts curl open like little petals. As soon as they come out I wrap them in a tea towel for five minutes or so; they steam a little, and the shell and the thin bitter skin underneath come away more easily. They’re best peeled while still warm — once they cool, they cling to their skins.

Choosing them matters as much as cutting them. I pick chestnuts that are heavy for their size, glossy and firm, with the shell tight against the nut. If a shell rattles or gives under my thumb, or has a tiny hole, the chestnut is probably dry inside or has had a visitor, and it goes back. At home I keep them in a paper bag in the fridge and use them within about a week; in a warm kitchen they dry out or go mouldy surprisingly fast.

Before they go in the oven, I put the cut chestnuts in a bowl of cold water for ten or fifteen minutes. A few float, and those are usually the empty or spoiled ones, so they go in the bin. The soak also puts a little extra moisture into the shell, which helps it steam open.

For the roasting, the oven goes to 200°C, or 180°C for a fan oven. I spread the chestnuts on a tray cut side up in one layer. Twenty minutes is usually right, but big ones may need twenty-five. I give the tray a shake halfway. They are done when the cuts have curled right back and the flesh inside is pale gold and gives when you press it.

Peeling takes a little patience. I squeeze each one gently so the shell cracks further, pull it away and rub off the thin brown skin underneath. If a chestnut is stubborn, it usually hasn't had quite long enough; I put those back for five minutes rather than fight them. I always check the inside as I go: the flesh should be creamy yellow; anything grey, black or powdery with mould goes in the bin.

Hot chestnuts straight from the oven are very hot inside, so I warn the children and let them cool on a plate for a minute or two. For small children, I break them into small pieces, as with any firm food that could block a little throat.

If we don't eat them all, the peeled chestnuts go into a covered box in the fridge and get used within two days, chopped into stuffing, stirred into soup or warmed through with Brussels sprouts and a knob of butter.

One important thing: all of this is about sweet chestnuts from a shop or market. Horse chestnuts from the park, the conkers children fill their pockets with, are not for eating. The sweet ones — soft, floury, smelling of the oven — are lovely just as they are with a cup of tea, or crumbled into a soup or over braised cabbage.