How to Make It
In a medium bowl, whisk the flour with the salt. Using a pastry blender or 2 knives, cut in the shortening and butter until the mixture resembles coarse meal with some pea-size pieces remaining. Stir in the water until the dough just comes together. Scrape the dough out onto a work surface, gather up any crumbs and pat the dough into a disk. Wrap in plastic and refrigerate until well chilled, about 1 hour.
On a lightly floured work surface, roll out the dough to a 12-inch round, a scant 1/4 inch thick. Ease the dough into a deep 9-inch glass pie plate. Trim the overhanging dough to 1 inch and fold it under itself. Crimp decoratively and chill the crust until firm, about 15 minutes.
Preheat the oven to 375°. Line the crust with parchment paper and fill with pie weights or dried beans. Cover the rim with strips of foil and bake in the lower third of the oven for about 20 minutes, until the crust is barely set. Remove the parchment and pie weights and bake for 5 minutes longer, until the crust is just set but not brown. Poke the bottom of the crust lightly to deflate it if it is puffed. Let cool; leave the foil strips on the rim. Lower the oven temperature to 350°.
In a medium bowl, whisk the sugar with the butter, then whisk in the eggs. Add the buttermilk, vanilla and a pinch of salt and whisk until incorporated. Stir in the coconut.
Pour the filling into the pie crust and bake for 45 to 50 minutes, until the custard is set and golden brown on top. Let the pie cool completely, then remove the foil, cut the pie into wedges and serve with ice cream.