Heat the oven to 200C/180C fan/gas 6, or to 200C if using an air fryer. Put each chestnut flat-side down on a chopping board. Hold the chestnut carefully and, using a sharp knife, cut a long slit or a cross in the top. Make sure you cut through the shell but not the nut inside. The shell is tough and flexible like a skin rather than rock hard like other nut shells, so a small kitchen knife works well.

Tip the nuts onto a baking sheet or into a roasting tin and arrange them cut-side up. Roast in the oven for 30 mins. If using an air fryer, arrange the nuts cut-side up in the air fryer basket. Roast for 8-10 mins. The cuts should open up and the shell will start to peel back. Cooking time will vary depending on the size of the chestnuts. If the shells aren’t peeling, roast for another 5-10 mins, keeping a close eye on them so they don’t burn.

Leave the nuts to cool in the tin or air fryer basket until they're just warm – they will be very hot inside. If you can, put a board on top of the tin or basket while they cool to trap the steam and make them easier to peel. Serve as they are for people to peel, or peel them yourself to use in a recipe.

If you peel them, you may want to remove the slightly fluffy inner membrane as well. If the membrane is difficult to get off (it shouldn’t be if you steam them as they cool), you can soak the nuts in boiling water for a minute to loosen, then drain and peel.