Preheat oven to 425; prepare pie shell: Prick the bottom of the crust with a fork and line it with pie weights (or a perforated nesting pie pan) to help the shell holds its shape; bake for 15 to 18 minutes, until it's lightly browned. Reduce oven heat to 400°F.
Allow the crust to cool slightly before removing the weights or nested pan -- if the crust still managed to bubble, just prick it gently with a fork; it'll deflate as it cools.
Prepare the filling: In a medium-sized mixing bowl, whisk together the sugar, flour and salt; add the eggs, cream, rum, and vanilla, and whisk together well.
Let the mixture sit for 5 minutes, or the time it takes to peel and dice the peaches; whisk again just before pouring the custard into the pie shell.
(This resting time allows the sugar to dissolve.) Pour the custard into the pre-baked pie shell, and spoon the peaches on top.
Some will sink; that's OK, they're supposed to.
Use a piecrust shield or aluminum foil to gently cover the outer edge of the crust.
Bake the pie in a 400°F oven for 20 minutes.
Make the topping while the pie bakes.
Gingered Streusel Topping:If you have a food processor, just place all the topping ingredients into the work bowl and process, using the steel blade, until crumbs begin to form.
To make by hand, whisk together the minced crystallized ginger, sugar, and flour, then stir in the melted butter.
After the pie has baked for 20 minutes (it will have just begun to set up around the edges), carefully sprinkle the streusel over the top, leaving the pie crust shield in place.
Bake for another 20 to 25 minutes, or until the pie has puffed, the streusel is very slightly browned at the edges, and/or an instant-read thermometer inserted into the center of the pie reads about 160°F.
Remove the pie from the oven, and cool it on a rack for about 2 hours before serving.