Cross-sections made in the flat side of the shells - see the "X's?"
To me, few things signal the arrival of autumn better than the sweet chestnut. As soon as I see them at the farmer's market, I happily scoop them up, filling a bag with them. Chestnuts have to be cooked before they can be eaten. The meats are large and sweet, and do well on their own as a snack, chopped and added to savory stuffings, or added to desserts. Peeling and roasting them is a bit time-consuming, but knowing a few tricks can help expedite the process.
Select chestnuts that are firm and heavy for their size. Pinch them - there should be some "give" between the shell and the nut, but they should not rattle around in the shell. Select nuts that do not have holes or blemishes. Chestnuts are highly perishable, so store them in a ventilated bag in the crisper drawer of your refrigerator. If you aren't going to use them within a few days, seal them in an airtight bag and freeze them. Don't leave them out at room temperature as they will develop mold and go rancid quickly.
A note about peeling chestnuts. There are two layers you have to peel through; the shell and the skin. The skin comes off more easily when the nut is hot; as the nut cools down, the skin hardens and becomes more difficult to get off. So, you need to keep the unpeeled ones warm while you're peeling others. I'll explain that method below. Another thing is, you have to cut "X's" in the shell otherwise the nuts will explode in the oven, making a mess.
Preheat the oven to 350 degrees F. With a sharp knife, cut an "X" through the shell on the flat side of each nut. Measure out a square piece of aluminum foil and place the chestnuts in it - don't overcrowd, maybe about 2 cups of chestnuts per foil square. Bring up the sides of the foil and crimp the ends together, creating a foil "bag." Leave a small hole at the top for ventilation. Add 1/4 cup of water to the makeshift foil bag. Place the foil bag and any other bags (depending on how many nuts you are roasting) on a baking sheet and place in the oven. Bake for 25 to 30 minutes. Remove from oven.
Leave one foil bag open but seal the others to keep the heat in. When the chestnuts in the opened bag are cool enough to handle (don't wait too long!) peel off the shells at the X which will now have its corners curled up. Slip off the skins. When you finish this batch start on another batch. Don't open the foil bags until you're ready to peel the nuts in them.
Peeled chestnuts need to be placed in an air-tight container and refrigerated if they aren't going to be used immediately. They can keep in the refrigerator for two or three days.
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(Images: Kathryn Hill)