I take the chestnuts and cut a small 'x' in the flat side. Then put in a pan, put in a hot Weber (maybe 325F or so) and roast for 10 minutes, check for done-ness and then keep going. I am looking for the 'x' cut to peel open. They burn easily. Now, we used to also use a popcorn basket for use over a flame, but, that broke a long time ago and did not get replaced.