Prepare:
Divide the dough in half and roll each portion into an 11-inch square, about ⅛ inch thick. Place on a baking sheet and refrigerate.
Peel, core, and cut into ¼-inch dice:
Place in a medium bowl and toss well with:
Transfer the pastry squares to a cutting board and trim ½ inch from all sides to make two 10-inch squares. Cut each into four 5-inch squares (or rounds if you prefer, using a large cutter). Spoon the apple mixture, dividing it equally, onto the center of the pastry squares. Lightly brush a ½-inch border on 2 adjacent edges of each pastry square with:
Form a triangular turnover by folding the dry corner of each square over the apples to the egg-washed corner; press the edges together with the tines of a fork to seal them. Brush the top of each turnover with egg wash, and cut 3 small slits in the top of each one. Arrange the turnovers at least 1 inch apart on 2 ungreased baking sheets and refrigerate for 30 minutes.
Position a rack in the lower third of the oven. Preheat the oven to 425°F.
Bake the turnovers until they begin to brown, about 15 minutes. Reduce the oven temperature to 350°F and bake until golden, 15 to 20 minutes more. Serve warm.