Sweet Potato Sonker by America's Test Kitchen

 Ingredients

Sonker
2  boxes Pillsubyr Just Unroll Pie Crust

1 large egg, beaten

2 cups apple cider

4 pounds sweet potatoes, peeled, quartered lengthwise, and sliced 1/4 inch thick

1 cup (7 ounces) packed light brown sugar

4 tablespoons unsalted butter, softened

2 1/2 tablespoons all purpose flour

2 tablespoons lemon juice

1 teaspoon vanilla extract

3/4 teaspoon ground cinnamon

1/2 teaspoon ground allspice

1/4 teaspoon salt

1 tablespoon granulated sugar

Custard Dip

2 cups whole milk

1/4 cup (1/34 ounces) sugar

2 teaspoons conrstarch

1/4 teaspoon ground cinnamon

1/8 teaspoon salt

1 1/2 teaspoons vanilla extract

Instructions:

1. For the Sonker: Working on lightly floured conter, unroll 2 dough rounds. Brush half of 1 round with egg and overlap with second round. Roll out dough to 17 by 13-inch rectangle and fit into 13 by 9-inch baking dish. Cover with Plastic wrap and refrigerate for 30 minutes.

Repeat shaping and rolling with remaining 2 dough rounds; reserve beaten egg. Trim dough into rectangle and cut into 13n 1-9inch strips. Transfer dough strips to parchment lined rimmed baking sheet, cover with plastic and refrigerate for 30 minutes.

2. Meanwhile, adjust oven rack to middle position and heat oven to 375 degrees. Bring cider to boil in Dutch oven. Place steamer basket in dutch oven and fill with sweet potatoes. Reduce heat to medium and cook, covered until potatoes are nearly tender, 20 to 30 minutes. Removed and reserve sweet potatoes leaving cide in pot.

3. Cook cider over high heat until reduced to 1/2 cup, about 5 minutes. Combine drained sweet potatoes, brown sugar, reduced cider, buter, flour, lemon juice, vanilla, 1/2 teaspoon cinnamon, allspice and salt in  a large bowl. Spread out sweet potato mixture on rimmed baking sheet and let cool to room temperature, about 20 minutes.

4. Scrape cooled sweet potato mixture into dough-lined dish and press into even layer. Brush edges of dough with reserved egg. With long side of dish facing you, lay 4 doughs trips lenghtwise over sweet potato mixture. Weave remaining 6 strips into lattice pattern. Press dough strips into bottom crust and trim excess. Fold dough sides inward under lip of baking dish and crimp with fork.

5. Combine granulated sugar and remaining 1/4 teaspoon cinnamon in bowl. Brush dough with resereved egg and sprinkle with cinnamon sugar. Cover with aluminum foil and bake for 15 minutes. Uncover and bake until deep golden brown, 55 to 60 minutes, rotating dish halfway through baking. Let sonker cool on wire rack for at least 1 1/2 hours before serving. (Sonker can be refrigerated, covered, for up to 1 day. Bring to room temperature before serving. 

6. For the custard dip: meanwhile, bring milk, sugar, constrach, cinnamon, and salt to simmer in medium saucepan over mediumheat. Reduce heat to medium-low and cook, whisking frequently, until slightly thickened, about 15 minutes. Off heat, add vanilla. Transfer to bowl and let cool to room temperature, about 30 minutes. Serve with sonker.