For number 20 in the list of 100 things to BBQ, a quick one, but a festive one... roasted chestnuts! :-)
As the song goes, these just need to be "roasted on the open fire". After I had finished cooking the pork shoulder for the boxing day pulled pork, there was still a good amount of direct heat coming from the mostly burnt out charcoal - so I put it to good use.
The only bit of prep I did was to crack the shells slightly, to make sure they didn't explode during cooking. You can do this with a sharp knife, and just open the shells slightly. But I chose to just use the heavy end of a metal garlic press (I didn't have a kitchen mallet to hand...) and gave each chestnut a decent whack to split the shells. It's best to leave the shells on for cooking, to protect the nut from most of the direct heat. You want the nuts to roast and toast - not fry and burn :-)
Then I placed them directly on to the cooking grate, above the coals, closed the lid and left them for around 10 minutes. Bear in mind that my charcoal had already been burning for 4 hours, so the heat was nice and low. If you were using hotter coals, don't leave them for as long (you may even have to position them slightly off to the side of the direct heat.
Finally, after removing the chestnuts from the BBQ and leaving them to cool slightly, it's just a matter of peeling and enjoying them while they are still warm. Singing along with Bing Crosby or Nat King Cole whilst eating these in encouraged! :-)