Place flour, coconut, sugar, and salt in work bowl of food processor and pulse a few times to combine. Add butter and pulse in short bursts until butter and flour are combined and mixture resembles small peas. Drizzle cold water over and pulse a few times, just until the water disappears into the dough. Turn dough and any unmixed bits out onto a piece of plastic wrap or waxed paper and mash into a disc. Wrap tightly and chill for at least 1 hour, and up to 1 week.

Make coconut crust by hand: On a cutting board, mince coconut then scrape into a large bowl. Add flour, sugar, and salt and stir to combine. Sprinkle cold butter over and use a pastry blender or your fingertips to work butter into flour until mixture resembles small pies. Drizzle cold water over and stir to combine.

Both methods: Turn dough and any unmixed bits out onto a piece of plastic wrap or waxed paper and mash into a disc. Wrap tightly and chill for at least 1 hour, and up to 1 week.

Roll coconut crust: Roll out dough on a well-floured surface into a 12- to 13-inch circle. Transfer to a 9-inch pie pan, being careful not to stretch the dough. Trim overhang to 1 inch (save the scraps, you may need them to patch the dough), then fold onto rim and flute with fingers and thumb. Transfer pan to freezer; chill until crust is solid, about 20 minutes.

Heat oven: To 400°F.

Bake crust: Prick cold crust all over with a fork. Lightly coat a piece of foil with butter or nonstick spray and press it tightly against every nook and cranny of the frozen crust. (This allows us to skip pie weights.) Bake for 20 minutes, then gently, carefully, slowly remove foil. If any holes or cracks have appeared, use scraps of leftover pie dough to patch them. Return crust to oven and bake for 10 to 12 minutes, until deeply golden at edges and lightly golden at the bottom. Remove from oven and let cool completely before using.

Toast coconut for garnish: (Since you have the oven on right now.) Reduce heat to 350°F. Spread coconut for topping on a large baking sheet and gently toast coconut until edges are golden brown, 7 to 8 minutes. Watch carefully and stir a few times. Almost everyone who toasts coconut flakes ends up burning them. Let’s beat the odds! [I genuinely want to put up a Days Since Someone Making This Recipe Last Burned a Pan of Coconut Flakes, but I’m going to have to start it at zero because: me.] When they’re the right color, let the fully cool and set aside.

Make coconut pastry cream: Whisk flour, salt, granulated or vanilla sugar, vanilla bean seeds, if using, until combined. Whisk in eggs, then milk and coconut milk, followed by shredded coconut.Place over medium heat on the stove and bring up to a simmer, stirring. Once simmering, stirring, until custard thickens, 4 to 7 minutes. Off the heat, whisk in butter, a few chunks at a time, vanilla extract, if using instead of a vanilla bean, and rum, if using. Scrape into bowl, press plastic wrap against the surface of the custard, and chill in fridge for several hours or overnight until fully cool (and has finished thickening). In a rush? I often set the bowl of custard inside a larger bowl of ice water, stirring occasionally, which can speed up the process.

Make whipped cream topping: Whip cream, sugar (to taste) and vanilla, until firm enough that peaks hold their shape.

At last, assemble your pie: When pastry cream and crusts are fully cooled, fill crust with the coconut pastry cream and smooth the top. Either pipe or decoratively spoon (I used a large cookie scoop) whipped cream topping on top, then garnish with toasted coconut flakes. Use a vegetable peeler to shave chocolate curls all over.