Preparation Preheat oven to 350°F with rack in middle. Bake sweet potatoes in a shallow baking pan until very soft, about 1 1/2 hours. Meanwhile, soak dried chestnuts (if using) in boiling-hot water 1 hour, then drain. Coarsely chop chestnuts (cooked or dried). While dried chestnuts soak, bring dried apple and juice to a simmer in a small saucepan, then turn off heat. Let steep, covered, 30 minutes. Drain off and discard apple juice. Cool baked potatoes to warm, then peel and mash with a potato masher. Transfer 2 cups mashed sweet potato to a bowl and reserve any remainder for another use. Increase oven temperature to 375°F. Whisk butter and sugars into warm sweet potato along with honey, nutmeg, cinnamon, and 1/2 teaspoon salt until smooth. Whisk in eggs, vanilla, cream, and milk, then dates, chestnuts, and apple. Bake in a buttered 1 1/2- to 2-quart baking dish (1 1/2 to 2 inches deep) until just set, 40 to 50 minutes (center will continue to set as it cools). Cool to warm on a rack, about 20 minutes. 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.
Preparation Preheat oven to 350°F with rack in middle. Bake sweet potatoes in a shallow baking pan until very soft, about 1 1/2 hours. Meanwhile, soak dried chestnuts (if using) in boiling-hot water 1 hour, then drain. Coarsely chop chestnuts (cooked or dried). While dried chestnuts soak, bring dried apple and juice to a simmer in a small saucepan, then turn off heat. Let steep, covered, 30 minutes. Drain off and discard apple juice. Cool baked potatoes to warm, then peel and mash with a potato masher. Transfer 2 cups mashed sweet potato to a bowl and reserve any remainder for another use. Increase oven temperature to 375°F. Whisk butter and sugars into warm sweet potato along with honey, nutmeg, cinnamon, and 1/2 teaspoon salt until smooth. Whisk in eggs, vanilla, cream, and milk, then dates, chestnuts, and apple. Bake in a buttered 1 1/2- to 2-quart baking dish (1 1/2 to 2 inches deep) until just set, 40 to 50 minutes (center will continue to set as it cools). Cool to warm on a rack, about 20 minutes. 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.