Ingredients
Method
Place a rack in lower third of oven and preheat to 350°. Crumble 9 graham cracker sheets (140 g) into food processor; add 1 Tbsp. granulated sugar and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt and process until crackers are very finely ground. Add 5 Tbsp. unsalted butter, melted, slightly cooled, and 1 tsp. vanilla bean paste or vanilla extract and pulse until the texture of wet sand.
Remove lid and blade from processor and mix crumbs with your hand or a rubber spatula to ensure there are no unevenly mixed crumbs.
Transfer crumb mixture to a standard 9"-diameter metal or glass pie dish and press firmly and evenly up sides and across bottom with a flat-bottomed measuring cup (building the sides first, then smoothing the bottom will make for a more even crust). Chill crust in the refrigerator 20 minutes (or, if you are short on time, in the freezer 10 minutes).
Place pie pan on a rimmed baking sheet if desired; bake crust until a deeper golden brown, 15–18 minutes. Let cool. Do ahead: Crust can be baked 2 days ahead. Store tightly wrapped at room temperature.
Whisk ½ cup heavy cream, 1 Tbsp. vanilla instant pudding mix, ¼ cup (50 g) granulated sugar, and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in a medium bowl until thick and mousse-like in texture (some of the sugar may remain undissolved). Cover with a lid or plate and chill until ready to use.
Vigorously whisk 3 large eggs, ⅓ cup plus 1 Tbsp. (50 g) all-purpose flour, remaining ⅓ cup (67 g) granulated sugar, and remaining 1½ tsp. Diamond Crystal or 1 tsp. Morton salt in a medium saucepan until smooth (no lumps of flour should remain). Add two 13.5-oz. cans unsweetened coconut milk and whisk to combine. Place over medium heat; bring to a simmer, whisking often and making sure to get into corners of pan, until bubbling and thickened, 8–10 minutes. Remove pudding from heat; add 6 Tbsp. unsalted butter, cut into pieces, and 2 tsp. vanilla bean paste or vanilla extract and whisk until combined.
Measure out 3 cups (570 g) pudding into a large bowl; stir in 1 cup (loosely packed; 75 g) sweetened shredded coconut and 2 tsp. coconut extract. Cover with plastic wrap, pressing directly onto surface, and chill until cool, 30–45 minutes.
Add ¾ cup bittersweet chocolate chips or bittersweet or semisweet coarsely chopped chocolate to remaining pudding in pan and stir until chocolate is melted and pudding is smooth. Scrape into crust and smooth surface with a small offset spatula. Chill, uncovered, until pudding is cool and set, 30–45 minutes.
Using a whisk, fold chilled cream mixture into coconut pudding, then scrape into crust over chocolate pudding. Smooth surface, mounding slightly in the center with offset spatula. Cover pie loosely with plastic wrap and chill until filling is cold and set, at least 6 hours (but chilling a full day is ideal).
Scatter toasted unsweetened coconut flakes over coconut filling just before serving pie. Do ahead: Pie (without coconut flakes) can be assembled 2 days ahead. Keep chilled.