Combine the apples, brown sugar, lemon juice, cinnamon and salt in a large bowl. Gently fold to coat the apples. Preheat oven to 400 and line with medium baking sheets with parchment paper. On a lightly floured surface, roll dough into a 12in circle about 1/8th thick. Transfer to pan with parchment paper. Arrange apple slices, leave 1 1/2in border around the edge. Fold the edge nearest to you toward the center and continue until all the edges are folded towards fruit. Brush egg wash over the crust and sprinkle with sugar. Bake 40-45min, until crust is golden and fruit is tender