Lattice Apple Pie with Mexican Brown Sugar

Put a large heavy baking sheet in middle of oven and preheat oven to 425°F.
Bring piloncillo, water, zest, spices, and 1/8 teaspoon salt to a boil in a small heavy saucepan, covered, stirring occasionally until piloncillo has dissolved. Remove lid and boil over medium-low heat until syrup is thickened and reduced to about 3/4 cup, 6 to 10 minutes. Discard zest and cool syrup slightly.
Meanwhile, peel and core apples, then cut into 1/2-inch-wide wedges.
Toss apples with flour, then with syrup.
Roll out 1 piece of dough (keeping remaining piece chilled) on a lightly floured surface with a lightly floured rolling pin into a 13-inch round, then fit into a 9-inch pie plate.
Trim edge, leaving a 1/2-inch overhang, and chill shell.
Roll out remaining piece of dough on a lightly floured surface with a lightly floured rolling pin into a 16-by 11-inch rectangle. Cut dough crosswise into 11 (1 1/4-inch-wide) strips.
Stir apple mixture, then spoon evenly into pie shell. Weave a tight lattice pattern over pie with pastry strips.
Trim all strips flush with edge of pie plate. Fold bottom crust up over edge of lattice and crimp. Brush lattice (but not edge) with milk and sprinkle with sugar.
Bake pie on hot baking sheet 20 minutes.
Reduce oven temperature to 375°F and bake until crust is golden and filling is bubbling, 50 to 60 minutes more. Cool pie to warm or room temperature, about 1 1/2 hours.