Ingredients
3 pounds apples (see cook's note), peeled, cored, and cut into 1/2-inch-thick slices (8 cups)
3/4 to 1 cup granulated sugar
1/2 teaspoon kosher salt (we use Diamond Crystal)
1 tablespoon apple-cider vinegar
1/2 teaspoon ground cinnamon
1/4 teaspoon ground ginger
1/8 teaspoon ground cardamom
1/8 teaspoon freshly ground black pepper
Pinch of ground cloves
3 tablespoons unbleached all-purpose flour, plus more for dusting
1/2 recipe Test Kitchen's Favorite Pate Brisée (1 disk)
1 large egg, lightly beaten
6 tablespoons unsalted butter, softened
1/4 cup packed light brown sugar
1/2 teaspoon baking powder
1/2 teaspoon kosher salt (we use Diamond Crystal)
3/4 cup unbleached all-purpose flour
1/2 cup quick-cooking rolled oats
Preparation
For the Filling: In a large heatproof bowl, toss together apples, granulated sugar (use 1 cup if your apples are very tart), salt, vinegar, and spices. Let stand at room temperature, stirring occasionally, for at least 3 hours, or refrigerate (covered) up to 24 hours.
Stir flour into macerated apple mixture, then set a colander over another bowl and drain, reserving liquid. Transfer liquid to a small saucepan; return apples to bowl. Bring liquid to a boil over medium-high heat, whisking constantly, until thickened to the consistency of loose pudding, 1 to 2 minutes. Stir back into apple mixture.
For the Crust: Preheat oven to 400°F, with a rack in bottom third. On a lightly floured surface, roll out disk of dough 1/8 inch thick (about 13 inches in diameter). Fit it into a 9-inch pie dish. Trim overhang to 1 inch, fold edges under, and crimp as desired. Brush edges of crust with egg and fill with apple mixture; refrigerate for 15 minutes (to help crust hold its shape in the oven).
For the Topping: In a medium bowl with an electric mixer, beat butter, brown sugar, baking powder, and salt until light and creamy, about 2 minutes. Add flour and oats and beat to combine.
Crumble topping over filling and bake for 20 minutes. Reduce oven temperature to 375°F and bake until golden brown all over and bubbling in center, 50 to 60 minutes more. (If the top browns too quickly, tent it with foil.) Transfer to a wire rack and let cool completely, at least 6 hours.
Try one of these formulas for the filling in this pie: 1 1/2 pounds Braeburn (sweet-tangy and firm) + 1 1/2 pounds Granny Smith (tart) + 1/2 pound McIntosh (classic apple flavor) or 1 1/2 pounds Golden Delicious (sweet-tangy and firm) + 1 1/2 pounds Granny Smith (tart) + 1/2 pound Macoun (classic apple flavor)
