Preheat oven to 425°F. Position one rack on bottom rung of oven and one in the center. Place a large cookie sheet on bottom rack of oven.
Unroll two circles of dough onto parchment-lined cutting board, with edges overlapping. Using a flour-dusted rolling pin, roll together cracks in the dough. Fold edges inward to create a rectangle, slightly larger than the baking sheet. Transfer dough to baking sheet, fitting edges up and over the sides of the pan. Refrigerate for 10 minutes.
Remove baking sheet from refrigerator and prick holes in dough with a knife. Place sheet on center rack of oven and bake for 15 minutes. Remove from oven and set aside. Reduce heat to 375°F.
Repeat the rolling process with remaining dough to create the top layer of pie. Refrigerate for 10 minutes.
Add thawed peaches, brown sugar, lemon juice, cinnamon and ginger to a large bowl and gently fold together with a spatula. Pour peach mixture into a strainer to drain excess liquid. Pour strained peaches evenly into par-baked crust, and cover with remaining dough.
Use a fork to crimp the edges of dough together around the edges of the baking sheet. Poke scattered holes in the dough to vent while baking (alternatively, use a knife to cut desired shapes out of dough).
In a small bowl, whisk the egg. Brush top crust with egg wash and sprinkle with brown sugar. Place pie in center rack of oven and bake for 70 minutes, rotating pan halfway through. Remove pie from oven when crust is golden and filling is bubbly. Let cool for one hour prior to serving.