1/4 cup (packed) golden brown sugar
2 tablespoons all-purpose flour
1 tablespoon lemon juice
2 teaspoons grated lemon peel
1/8 teaspoon ground nutmeg
3 pounds Golden Delicious apples, peeled, cored, thinly sliced
Add 6 tablespoons ice water and process until moist clumps form, adding more water by teaspoonfuls if dough is dry. Gather into ball; divide into 2 pieces.
Flatten each into disk. Wrap each in plastic; chill 2 hours. (Can be made 2 days ahead. Keep chilled. Let dough soften slightly before rolling out.)
Position rack in lowest third of oven and preheat to 400°F. Mix first 6 ingredients in large bowl. Add apples and toss to blend.
Roll out second dough disk on floured surface to 13-inch round. Cut into twelve 1-inch-wide strips. Arrange 6 strips across pie. Form lattice by arranging 6 strips diagonally across first strips. Gently press ends into crust edges.
Brush lattice with milk. Sprinkle lightly with additional sugar. Bake pie 10 minutes. Reduce oven temperature to 375°F. Continue baking until juices bubble thickly and crust is deep golden, covering edges with foil if browning too quickly, about 1 hour 20 minutes. Cool on rack 1 hour. (Can be made 8 hours ahead. Let stand on rack.)