Bourbon Sweet Potato and Apple Casserole with a Pecan Crust

This recipe comes from the November 2010 edition of Fine Cooking. The author writes,
“This dish is nothing like the marshmallow-topped Thanksgiving sweet potato casserole of old. Sautéed apples, a crunchy pecan crust, and spicy mashed sweet potatoes make for a sophisticated update.”

Bourbon Sweet Potato and Apple Casserole with a Pecan Crust
Serves 8

Ingredients
3 to 3¼ pounds sweet potatoes
4 tablespoons unsalted butter, plus more for the pan
4 ounces toasted and very finely chopped pecans (about 1 cup)
1⅓ cups fresh breadcrumbs
2 tablespoons finely chopped fresh parsley
kosher salt
1 cup heavy cream
8 ¼-inch-thick slices fresh ginger, unpeeled and crushed
2 whole star anise
1 2- to 3-inch cinnamon stick
2 tablespoons plus 2 teaspoons bourbon
1½ teaspoons pure vanilla extract
1¾ pounds apples, peeled, quartered, cored, and thinly sliced

Directions
1. Position a rack in the center of the oven and heat the oven to 400 degrees. 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, reduce the oven temperature to 375 degrees. Discard the sweet potato 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). Set aside.
2. Now prepare the crumb topping. Melt 2 tablespoons of the butter and combine with the pecans, breadcrumbs, parsley, and two big pinches of salt in a small bowl. Set aside
3. Combine heavy cream, ginger, star anise, and 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 tablespoons of the bourbon, the vanilla extract, and ¼ teaspoon salt. Set aside.
4. In a skillet, melt the remaining 2 tablespoons of butter over medium-high heat. Add the apples, season with ¼ teaspoon 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 teaspoons bourbon and stir until it evaporates, a few seconds. Pour in ⅓ 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.
5. Butter a shallow 9x13-inch baking dish. 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 degrees until the crumb topping is dark brown (it will be browner around the edges) and the casserole is heated through, about 25 minutes.