Preheat oven to 425 degrees F.
Score each chestnut on the round side (see note above). Using a bread knife or another sharp, serrated knife, apply gentle pressure until you break the surface, then slash all the way across and through the round side of the shell. Cut deep enough to penetrate the hard shell but not too deep as to cut well into the chestnut. Place the scored chestnuts in a pot filled with enough cold water to cover. Bring the pot to a boil, add a big pinch of salt, and allow to simmer for one minute.
Drain the chestnuts and place on a baking sheet with sides. Bake in the preheated oven for 15 minutes. You will be able to tell that the chestnuts are ready to be shelled if the outer shell starts to peel back from the score mark and you can see the golden chestnut within.
Remove the baking sheet from the oven and immediately cover with a tea towel for 15 minutes. This will allow the chestnuts to steam slightly, making them easier to peel. (Occasionally, there will be a chestnut that is hard to peel. It is the chestnut, not you!)
After 15 minutes, remove the towel, peel, and enjoy warm. You may also refrigerate or freeze for later use.
If enjoying right away, we like to brush the warm chestnuts with just enough olive oil to allow a light sprinkling of sea or kosher salt to stick.
