Baked in the oven Chop the chestnuts. Soak your eyes in lukewarm water for a few hours. Preheat the oven to 200 degrees. Put the chestnuts in a baking sheet and put in the oven. If you haven’t had time to soak the chestnuts before, pour a little water into the baking tray. While baking, shake the baking sheet several times to turn the chestnuts over and simmer evenly on all sides. After 30-40 minutes, remove the roasted chestnuts from the oven. When good, it exudes a very delicate scent and the peel opens along the cuts.