Place chestnuts in a colander and rinse under cold running water. Drain.
Place the flat side of the chestnut down on a cutting board. The rounded side, (aka the belly side) should be facing up. Hold the chestnut firmly and cut horizontally across the rounded side using a sharp paring knife or a chestnut knife, if you have. Then turn the chestnut 90 degrees and make a second cut forming an X. As you are cutting, do your best not to score the inner skin. Continue with the rest of the chestnuts.
Transfer the now-cut chestnuts into a bowl. Cover it with cold tap water and let them sit for an hour.
Preheat it to 425 degrees. Drain chestnuts (no need to dry) and place them on a baking sheet pan in a single layer. Roast for 25-30 minutes*1 keeping a close eye on it and turning a few times if necessary. They should be fully roasted when the skins have pulled back/opened and the flesh inside has softened.
Remove from the oven and place the now-roasted chestnuts in a kitchen cloth. Collect the edges of the cloth in the middle and turn it into a small pouch. Let them steam in the “pouch” for 10-15 minutes. Alternatively, you can use a paper bag. Simply place the hot roasted chestnuts in it, roll the bag trapping the steam inside and let it steam for 10-15 minutes.
Being careful not to burn yourself, gently squeeze chestnuts using the kitchen cloth or the paper bag as a shield to help remove the skins. You should hear the crackling sound of the roasted skins as you do so.
To peel, transfer the roasted chestnuts onto a platter and remove the outer shell of the chestnuts when they are still hot by gently pulling back on the scored “X”, peeling away the papery skin and exposing the yellow flesh inside. If you are unable to remove the fuzzy inner skin by hand, use a small sharp knife to peel it, being careful not to pierce the yellow nut inside.*2 Discard the bad chestnuts that are spoiled inside.
Enjoy roasted chestnuts on their own or use it with your favorite herbs or seasoning.