1 To prepare dough, combine flours, salt, and 1 tablespoon sugar in a food processor or mixer bowl.2 Add butter and mix with a fork or pastry cutter until pieces of butter are uniformly pea-sized. Add water, one tablespoon at a time, until dough holds together when pinched, but is still crumbly. 3 Place dough onto a lightly-floured surface and work it gently into a smooth ball. Wrap in plastic and refrigerate for 20 minutes. 4 Preheat oven to 375°F. While dough is being refrigerated, prepare the apple filling. Slice halved apples into 1/8-inch-thick pieces. 5 Gently toss apples with lemon juice, 2 tablespoons butter and sugar in a large mixing bowl. Set aside. 6 To prepare for filling, place chilled dough onto a floured piece of parchment paper, large enough to line a large rimmed sheet pan approximately 12 by 16 inches. 7 Roll dough to form a rectangle, about 1/8 inch thick. Fold over excess dough over to form a decorative, free-form border.8 Transfer dough and parchment paper to a rimmed baking sheet and brush with remaining 1 tablespoon melted butter. Sprinkle edges with remaining 1 tablespoon sugar.9 To fill, shingle sliced apples in a diagonal pattern, overlapping each by half an apple slice (side to side and top to bottom).10 Bake until crust is golden brown and apples begin to caramelize, about 40 minutes.