This was an experiment with no prior knowledge or experience. If you have actually roasted chestnuts before, please offer some input in the comments!
December 14th will be Roast Chestnuts Day according to the sources I use when scheduling Facebook posts for the library where I work, so I decided it would be worth trying this holiday treat so lauded in song this time of year. The instructions I followed were an amalgamation from several sources.
Cut an X in the chestnut hull to vent steam and provide a starting point for it to split open.
Soak for 30-60 minutes in a bowl of water so there is more moisture to steam open the hulls
Preheat oven to 400°F and bake for 20-30 minutes.
Peel the shiny outer skin and inner pithy later that form the shell in order to eat the nut kernel inside.
Two roasted nuts, one showing the expansion along the slit and one split in half to reveal the internal structure
I think I need to cut a deeper and larger X next time. I may also need to bake them longer. Nonetheless, it was a tasty experiment. The consistency of the roasted chestnut is similar to a baked potato, and the flavor is slightly sweet and slightly nutty. Peeling away the hull was a bother though. Either the nut is too hot to handle, or the hull has started to harden again.
Here you can see the shiny outer layer, the fibrous pithy inner layer, and the pale nut meat in the center.
This one is still intact after my clumsy and barbaric removal of the shell.
Inside, it is almost like a walnut in that there seem to be multiple chambers separated by a thin membrane of shell. However, there is no hollow space whatsoever.
I would recommend giving this a try if you want an interesting experiment for yourself. Please let me know how it goes if you do, and what you can do better!