Preheat the oven to 425°. Place the chestnuts on a dish towel. This way it will keep the chestnuts from rolling. Use a sharp knife to cut an X into one side of the chestnut to allow the steam to escape while roasting, otherwise the chestnuts will explode. Place each chestnut with the cuts facing up onto a cookie sheet. Roast 20 to 30 minutes- until chestnuts are tender, easy to peel, golden brown in color, and the shells are beginning to open.