Preheat oven to 425°: Place oven rack in the middle.
Make an incision by laying the chestnut flat on your cutting board. With a serrated knife, make a lengthwise slit down the entire middle surface, on the long side. Make sure you hold down the chestnut firmly on the cutting board (be careful not to cut yourself as the outer shell is very slippery).
Place the chestnuts in a pot of cold water. As soon as the water begins to boil, remove the chestnuts with a slotted spoon and place on a shallow baking pan.
Place the chestnuts with the flat side down, the cut side up in a single layer in your baking pan. Roast in the oven for about 15-20 minutes.
Once you have obtained perfectly oven roasted chestnuts, remove from the oven and wrap them in a clean tea towel. Allow the wrapped chestnuts to sit in the towel for about 10-15 minutes.
You can roast as many chestnuts as you like.Please keep in mind that the nutritional information provided below is just a rough estimate and variations can occur depending on the specific ingredients used. *method in recipe inspired from Chef John