Preparation

Bake the sweet potatoes

• Position a rack in the center of the oven and heat the oven to 400°F. Line a rimmed baking sheet with aluminum foil. Prick the sweet potatoes all over with a fork and bake them on the sheet until completely tender when pierced with a fork, 55 to 60 minutes. Let rest until cool enough to handle. Meanwhile, if not working ahead, reduce the oven temperature to 375°F.
• Discard the skins and put the flesh in a medium mixing bowl. With a potato masher, work the sweet potatoes until they’re well mashed (they don’t have to be perfectly smooth).

Make the crumb topping

• Melt 2 Tbs. of the butter and combine with the pecans, breadcrumbs, parsley, and two big pinches of salt in a small bowl.

Infuse the cream

• 将鲜奶油、姜、八角茴香、和cinnamon stick in a small saucepan. Bring to a full boil (watch carefully so that it doesn’t boil over) and remove from the heat immediately. Let steep for 15 to 20 minutes. Strain through a fine sieve into a liquid measuring cup, pressing down on the solids with a spatula to extract all of the liquid. Stir in 2 Tbs. of the bourbon, the vanilla extract, and 1/4 tsp. salt.

Cook the apples

• In a 12-inch nonstick skillet, melt the remaining 2 Tbs. butter over medium-high heat. Add the apples, season with 1/4 tsp. salt, and toss well. Raise the heat to high and cook, stirring frequently, until soft and lightly browned, 8 to 9 minutes. Lower the heat if the apples are getting too dark, but not so much that they soften without browning.
• Turn off the heat, carefully add the remaining 2 tsp. bourbon and stir until it evaporates, a few seconds. Pour in 1/3 cup of the infused cream and stir until the apples have absorbed most of it, a few more seconds. Set the pan aside and let the apples cool for about 15 minutes, turning them occasionally to release steam.

Assemble the casserole

• Butter a shallow 3-quart baking dish (9×13-inch works well). Add the remaining cream to the mashed sweet potatoes and mix thoroughly. Season to taste with salt. Arrange the apples across the bottom of the baking dish. Spread the sweet potato mixture over the apples in an even layer. Top with the pecan-crumb mixture.
• Bake the casserole at 375°F until the crumb topping is dark brown (it will be browner around the edges) and the casserole is heated through, about 25 minutes.

Make Ahead Tips

You can bake and mash the sweet potatoes and make the crumb topping a day ahead (cover both and refrigerate). Bring the potatoes and crumb topping to room temperature before assembling the dish. You can also assemble and refrigerate for up to 8 hours before baking. Return to room temperature before baking.