In a large bowl, combine the granulated sugar, dark brown sugar, flour, cornstarch, ginger, cinnamon, and salt. Add the pear and lemon juice and toss to combine.
Arrange the pears in the center of the dough, leaving a 2-inch border around the perimeter. You can just pile them on or arrange in concentric circles. Pour any spare juices on top.
Fold the edges over into the center, pleating the dough as you go. Brush the dough with the egg wash and sprinkle with the turbinado sugar. Refrigerate for 15 minutes.
Meanwhile, preheat the oven to 375 F (190 C).
Bake until the filling looks soft and jammy and the crust is golden brown, about 50 minutes. Cool slightly before slicing and serving.