Step 1: Choosing your Chestnuts
The chestnut season is October through the end of December, so any for sale outside that window will likely be either too young or too old. Neither are desirable.
You want glossy, firm nuts that have little, if any, space between the shell and the meat inside.
Step 2: Tools of Tastiness
Step 3: Cutting Technique
Starting on the flat underside of each nut, use a sharp paring knife and make an 1/8" deep incision that goes through the skin, the fuzzy papery layer, and just barely pierces the flesh. Slowly and carefully continue the cut almost all the way around the nut, stopping just short of meeting back up with where you started.
The reason you make this cut is so that the nuts are more accessible / easier to peel after they are roasted.
NOTE: The classic chestnut cut is an 'X' on the flat side. Feel free to do this if you prefer traditional / old school ways. : )
Step 4: Roasting Time!
Give the pan a little shake at 15 min. to make sure they cook evenly.