In the bowl of a food processor fitted with a metal blade, combine flour, coconut, diced butter, sugar and salt and pulse to form coarse crumbs. Gradually add water, 1 tablespoon at a time, pulsing each time. Use only as much water as needed for the dough to hold together when pressed gently between your fingers (don't work dough with your hands, just test to see if it is holding). The dough will not form a ball or even clump together in the processor, it will be quite loose.
Place a large sheet of plastic wrap on the counter and dump the coconut dough onto it. Pull plastic wrap around dough, forcing it into a rough flattened round with the pressure of the plastic wrap. Refrigerate 30 to 60 minutes before rolling.
When ready to roll dough, unwrap round of coconut dough and place it on a lightly floured board. Flour rolling pin and your hands. Roll out dough in a circle about 1/8-inch thick. Occasionally lift dough with a bench knife or scraper to check that it is not sticking, and add more flour if it seems like it's about to stick. Trim to a 12- to 13-inch round. Transfer rolled dough to a 9-inch pie pan. Ease dough loosely and gently into pan. You don't want to stretch dough at his point, because it will shrink when it is baked.
Trim any excess dough to 1- to 11/2-inch overhang. Turn dough under along rim of pie pan and use your fingers and thumb to flute the edge. Refrigerate unbaked pie shell for at least 1 hour before baking (this prevents the dough from shrinking in the oven).
When ready to bake piecrust, preheat oven to 400 degrees. Place a piece of parchment in pie shell, with sides overhanging the pan, and fill with dried beans (this prevents the bottom of the shell from puffing up during baking). Bake piecrust for 20 to 25 minutes, or until pastry rim is golden. Remove pie pan from oven. Remove paper and beans and return piecrust to oven. Bake for an additional 10 to 12 minutes, or until bottom of crust has golden brown patches. Remove from oven and allow pie shell to cool completely.
DAHLIA TRIPLE-COCONUT CREAM PIE