Roast chestnuts

Heat the oven to 200C/180C fan/gas 6. Arrange each chestnut flat-side down on a chopping board. Working with one at a time, carefully hold the chestnut and, using a small, sharp knife, cut a cross in the top. (Try to cut just through the shell, avoiding the nut inside.) Repeat with all the chestnuts. Transfer the chestnuts to a large heatproof bowl, cover with just-boiled water, cover with a plate and leave to sit for 3 mins.

Put a large sheet of foil on a large baking tray, arrange the chestnuts in the centre and loosely gather up the edges to enclose the chestnuts and make a parcel, leaving an opening at the top.

Roast the chestnuts in the foil parcel until the outer shells begin to curl and the chestnuts are cooked through, about 25-30 mins. Remove from the oven, scrunch up the foil to fully close the parcel, and leave to sit for a further 5 mins. Tip the chestnuts onto a serving plate or platter, scatter with sea salt flakes, then serve.