Chestnuts are a favourite type of nuts, especially as they evoke winter and Christmas times. They depart from the norm of other culinary nuts as they are better cooked and have little protein or fat. They can be cooked grilled (especially in the streets), grilled or boiled, and some even recommend a combination of both ).
Make a slit in each nut, making sure to cut through the shell but not the nut inside. Roast for 30 mins in a 180-200°C oven. The cuts should open up and the shell will start to peel back.
Many say this is not the best way for direct consumption (but to use in flour, purée, etc.), although this cooks them in a distinctive, creamy and sweet way that is a nice alternative to roasting. Also make a slit, place in a bowl covered with cold water, bring to a boil and simmer for 5 to 10 minutes.