In a medium-sized bowl, whisk the flour with the salt and ground coconut shreds.
Add the cold cut pieces of butter and shortening to the flour, toss to coat. Use your fingers to cut in the shortening and butter into the flour mixture until the mixture resembles coarse meal with some pea-sized pieces remaining.
Gradually stir in the water with a fork until the dough just comes together.
Scrape the dough out onto a work surface, lightly knead and gather up any crumbs and pat the dough into a 6-inch round disk. Wrap in plastic and refrigerate until chilled, about 1 hour.
On a lightly floured work surface, roll out the dough to a 12-inch round, about ¼-inch thick.
Ease the dough into a deep 9-inch to 9 ½-inch glass pie plate. Trim the overhanging dough to 1 inch and fold it under itself. Decorate the edges as desired and chill the crust until firm, about 15 minutes.
Preheat the oven to 375°F.
Place the pie plate on a sheet pan. 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 20 minutes, until the crust is barely set.
Remove the parchment and pie weights and bake with the foil on the edges for 5 minutes longer, until the crust is just set but not brown.
Lightly poke the bottom of the crust a few times to deflate if it is puffed. Let cool; leave the foil strips on the rim.
Lower the oven temperature to 350°F.
In a medium-sized bowl, whisk the sugar with the melted butter. Whisk in eggs until smooth. Add the buttermilk, vanilla and a ⅛ teaspoon salt and whisk until incorporated. Stir in the coconut.
Place pie pan on a sheet pan. Pour the filling into the pie crust. Line the edges of the pie with foil.
Bake for 45 to 55 minutes, until the custard is set (not jiggly in the center) and golden brown on top. Remove the foil after 40 minutes of baking. If crust starts to brown too quickly, add foil back on the edges.
Carefully transfer the pie to a cooling rack. Let the pie cool completely, then cut the cake into wedges and serve with ice cream.
The pie can be covered and refrigerated for up to 5 days. Slice and reheat in the oven for a few minutes until the cake is warm and ready for eating!