Think of the best sweet-potato pie you've ever eaten and then take away the crust so you can revel solely in its silky goodness. A bite of this pudding is full and round, with hits of chestnut and dried fruit.
Cooks' notes:
·Sweet potatoes can be baked and mashed 1 day ahead. Chill, covered.
·Chestnuts can be soaked, drained, and chopped 1 day ahead. Chill, covered.