I realize that the above photo (I didn’t even brush away the crumbs, for shame) is not likely to make you want to make this cake. But I would be sorry because you would be missing out on such a lovely, lovely cake. It truly is like eating cloud, lemon-scented, chestnut-tinged cloud. The distinctive bittersweet taste of chestnut registers first, giving way to pleasantly tingling lemon.
The first time I made this, I used creme fraiche as per the recipe. This time, I used Greek yoghurt, and while both are delicious, I actually prefer the lightness of this version. (Though it’ll make a less pretty, more delicate, soufflé-like cake with a crumply top.) Put away some for the next day if you can, the taste deepens and gets much better.
Take the little morsel as a sign—i had to squirrel some away for myself otherwise I wouldn’t have had any leftovers!