Cut a 1cm (1/2 in) cross on the flat side of each chestnut. Be sure to cut through the chestnut's shell to prevent the chestnut from exploding.
Place the chestnuts in a shallow roasting tin and roast for 25 to 30 minutes.
Allow to cool and peel off the chestnuts' shells.
Place chestnuts in a frying pan with butter and saute over high heat until the butter is melted and the chestnuts are well coated. Place pan in oven and roast until they are golden on top. Sprinkle with salt and cinnamon.