Ingredients
3 tablespoons unbleached all-purpose flour, plus more for dusting
2 recipes Test Kitchen’s Favorite Pate Brisee, each shaped into a rectangular disk
4 tablespoons unsalted butter, room temperature, plus 2 tablespoons, refrigerated and cut into small cubes
1/2 cup packed light-brown sugar
1 teaspoon ground cinnamon
1/2 teaspoon kosher salt
4 pounds assorted apples, such as Jonagold, Cortland, Granny Smith, and Empire, peeled, cored, and cut into 1/4-inch slices
2 tablespoons fresh lemon juice
6 tablespoons granulated sugar
1 teaspoon pure vanilla extract
1 large egg, lightly beaten
Fine sanding sugar, for sprinkling
Preparation
On a lightly floured piece of parchment, roll one disk of dough into a 12-by-17-inch rectangle. Transfer crust to a 10 1/2-by-15 1/4-inch rimmed baking sheet or jelly-roll pan and press into bottom edges and up sides. Fold overhang under and around edge. Refrigerate 30 minutes.
In a small bowl, combine room-temperature butter, brown sugar, cinnamon, and 1/4 teaspoon salt. On a lightly floured piece of parchment, roll second disk of dough into a 12-by-16-inch rectangle. Evenly spread butter mixture over dough all the way to ends, then, starting at a long edge, tightly roll into a log. Transfer to a baking sheet and refrigerate until firm, about 30 minutes.
Preheat oven to 425 degrees with a rack in lower third and a foil-lined baking sheet on a rack below. In a large bowl, toss together apples, lemon juice, granulated sugar, flour, remaining 1/4 teaspoon salt, and vanilla. Fill piecrust with apple mixture and dot with cold butter.
Cut dough log into 1/4-inch slices, rotating with each slice to keep slices round. (You’ll need 63 slices total.) Arrange slices over apple mixture, slightly overlapping, in nine rows of seven. Refrigerate until firm, about 30 minutes.
Brush top of pie with egg wash and sprinkle with sanding sugar. Bake until top crust is just set, 20 minutes. Reduce temperature to 375 degrees and continue baking until crust is golden brown and juices are bubbling, about 1 hour. Let cool completely on a wire rack. Slab pie tastes best the day it’s made.
If you have extra cinnamon-swirl dough slices leftover, you can bake them on a parchment-lined baking sheet at 400°F until they become golden and crisp, about 12 minutes.
