Preheat the oven to 375 degrees.
Press pie crust into a 9 inch pie plate. Refrigerate while you prepare the remaining ingredients.
In a medium sized bowl, whisk together sugars, flour, cinnamon, ginger and salt. Drizzle melted butter over the top and use your fingers to work the butter into the flour mixture until coarse crumbles form. The mixture will probably seem wetter than typical crumb topping mixtures.
In another bowl, toss the peach slices with the cornstarch, lemon juice, and about 3/4 cup of the butter mixture. Place in the pie crust.
Crumble the rest of the butter mixture on top of the peaches. Don't be afraid to pile it high. It may seem like a lot, but trust me...it's just perfect!
This step isn't 100% necessary, but if you have time, it can be helpful to refrigerate the assembled pie for 15-30 minutes to help the crumbs keep their form while baking.
Place the pie on a baking sheet covered with parchment paper--there will likely be spillage!--and bake for 45-50 minutes or until filling is bubbly and topping is golden brown. If it's getting too browned after 30 minutes, cover with foil for remaining baking time.