Cook the chestnuts for 30 minutes in boiling salted water.
Drain and cool the chestnuts. Cut an X into the skin of each chestnut. This is important for two reasons: first, it stops the chestnuts from exploding. Second it makes them much easier to peel.
Spread the chestnuts out on a Drip Tray.
Insert the drip tray in The Otto Grill on the highest level and turn The Otto Grill on high heat. Roast until the skin starts to pop crack and blacken a little. Giving the nuts a little mix every now and then with a pair of tongues will help even cooking.