(Serves 4 to 6)
1 cup unbleached all-purpose flour, plus more for dusting the pan
1 Tbs granulated sugar
1/2 cup (1 stick) cold unsalted butter, cut into 1/4 inch pieces
3 to 4 Tbs ice water
1/2 tsp salt
2 large, tart, firm apples, cored and cut into 1/4-inch slices
2 large, sweet, soft apples, cored and cut into 1/4-inch slices
1/3 cup packed light brown sugar
1 tsp grated zest from one lemon
1/2 tsp vanilla extract
1 tsp milk
Crust - Mix flour, salt and sugar in a medium bowl. Scatter the butter pieces into the flour mixture; cut the butter into the flour until the mixture is pale yellow and resembles coarse crumbs with butter bits no larger than small peas.
Sprinkle 3 Tbs ice water over the mixture. With the blade of a rubber spatula, use a folding motion to mix. Press down on the dough with the broad side of the spatula until the dough sticks together, adding 1 Tbs more ice water if the dough will not come together. Place the dough on a sheet of plastic wrap, and press into either a square or a circle, depending on whether you are using a square or round pan. Wrap the dough in the plastic, and refrigerate at least 1 hour or up to 2 days before rolling out.
Assembly - Adjust the oven rack to the middle position, and preheat the oven to 425 degrees.
If the dough has been refrigerated longer than 1 hour, let it stand at room temperature until malleable.
Toss the apple slices, brown sugar, lemon zest, and vanilla together in a large bowl until the apples are evenly coated with the sugar. Place the apples in an 8-inch square or 9-inch round glass baking pan.
Roll the dough on a lightly floured work surface or between two sheets of wax paper to a 10-inch square or circle. Trim the dough to the exact size of the baking dish.
Place the dough on top on the apples. Leave a 1/4-inch gap between the dough and the sides of the pan to allow steam to escape as the fruit bakes. This will keep the crust from getting soggy. Brush the dough with the milk, and sprinkle with the cinnamon sugar mixture. Cut four 1-inch vents into the dough.
Bake until golden brown, 35 to 40 minutes.
Score the pastry in a wide grid pattern with a knife as soon as it emerges from the oven. Use the edge of a spoon or spatula to press the edges of the crust squares down into the fruit without completely submerging them. Because the crust will soften quickly, serve pandowdy warm.