There's nothing like a bag of hot, roasted chestnuts to warm you up on a cold winter's day. Not only does the hot, roasted flavor make the chestnuts taste best, but the outer shell and internal skin is much easier to peel when hot. It takes roughly about 20 minutes to roast raw chestnuts in an oven or over an open fire. Use the same basic process to reheat roasted chestnuts if they cool down before you get them all peeled. Or peel hot, roasted chestnuts in advance and reheat them before serving.
Preheat your oven to about 350 degrees Fahrenheit. Adjust the oven rack to the center position.
Spread the chestnuts on a rimmed baking sheet in an even layer. If the nuts are still in their outer shell, place them with the flat sides facing up. The flat side is usually scored with an "X" or a slit before roasting.
Place the pan in the oven and roast them for about five minutes or until evenly hot. Open the oven every minute or so and shake the pan gently to move the chestnuts around on the pan.
Remove the chestnuts from the oven and immediately place them in a brown paper sack to keep them warm.