Chocolate Chestnut Cake with Chestnut Mousse

When I was little, I spent lots of time alone with my nanny, Auntie Beth, and that was always something I looked forward to. One of the things we did was build a fire with chopped wood, score chestnuts, wrap them in foil, and throw them in the embers. When we took the chestnuts out, they were lovely. In America, that’s how most people know this hard-shelled, meaty-centered entity, as something roasting on an open fire and being peddled by a street-cart vendor. Otherwise, it