2 pounds peeled chestnuts
1 small fennel bulb, halved, a few fronds chopped and reserved for garnish
2 ribs celery, roughly chopped, a few leaves chopped and reserved for garnish
2 small bay leaves
3/4 cup heavy cream
4 tablespoons unsalted butter, cut into small pieces
3/4 cup whole-milk ricotta, at room temperature
Preheat oven to 375 degrees. Spread chestnuts in a roasting pan and roast until lightly golden, about 25 minutes.
Transfer to a deep, heavy pot. Cover with cold water, and add fennel, celery, bay leaves and a pinch of salt. Place over medium heat and simmer until the chestnuts are very soft but still whole, about 25 minutes. Drain cooking liquid and reserve. Discard fennel, celery and bay leaves.
Stir cream and butter into chestnuts, adding reserved cooking liquid if mixture is very thick. Gently reheat on a low burner, then transfer to a warm serving platter. Top with the ricotta and sprinkle with salt and the chopped fennel and celery tops.