Ingredients
Method
Position rack in bottom of oven; preheat oven to 350°F. Spread 3 cups unsweetened coconut flakes on a rimmed baking sheet and toast, stirring once or twice, until golden brown and fragrant, 8–10 minutes. Let cool.
Heat 1¾ cups whole milk in a small saucepan until almost boiling. Add half the toasted coconut (1½ cups), stir, and cover. Let steep 1 hour.
Roll out 1 disk Our Favorite Pie Crust, chilled, on a lightly floured surface to a 13" round. Wrap dough loosely around floured rolling pin, then release into pie plate. Lift up edges and allow dough to slump down into dish. Trim edges to leave a 1" overhang and crimp as desired. Freeze dough at least 15 minutes or chill, covered, up to 24 hours.
Line dough with parchment paper or aluminum foil and fill with dried beans or pie weights. Bake crust, rotating halfway through, 20 minutes. Remove weights, pierce bottom of crust all over with a fork, and continue to bake until very light brown and dry, about 10 minutes more. Let cool.
Strain toasted-coconut milk through a fine-mesh sieve into a large saucepan; discard solids (you should have about 1½ cups milk; add whole more milk if necessary). Add 2¼ cups coconut milk (not low-fat) and bring just to a simmer over medium-high heat. Remove from heat.
Pour remaining ¾ cup cold whole milk into a small bowl and sprinkle one (¼-oz.) envelope powdered unflavored gelatin (about 1 Tbsp.) over. Let sit 10 minutes. Whisk 7 large egg yolks, 1 cup (200 g) sugar, 6 Tbsp. cornstarch, and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in a large bowl. Add gelatin mixture and whisk until smooth.
Whisking constantly, slowly pour half of the coconut milk mixture in a thin stream into egg mixture. (A wet towel under bowl with egg mixture will help stabilize it.) Pour everything back into saucepan and cook over medium heat. Cook, whisking constantly, until mixture begins to thicken and starts to bubble, then continue to cook about 1 minute more so it doesn't taste starchy.
Strain through a fine-mesh sieve into a clean large bowl. Add 1 Tbsp. unsalted butter and 1 Tbsp. vanilla paste or extract and stir to combine. Press plastic wrap against surface of mixture and chill until cool, but not cold, 2½–3 hours. (You can speed up the process by stirring from time to time or placing bowl with filling in a large bowl of ice water.)
Using an electric mixer on medium-high speed, whip 1½ cups heavy cream until medium peaks form in a medium bowl. Working in 3 batches, gently fold cream into coconut filling until just incorporated. Sprinkle half of the remaining toasted coconut into bottom of prepared pie shell. Carefully spoon pie filling over coconut, mounding it in the middle and making decorative swirls with the back of a spoon. Chill at least 2 more hours to set.
When ready to serve, garnish pie with remaining toasted coconut. Do Ahead: Pie crust can be baked 1 day ahead. Store cooled crust, loosely wrapped at room temperature. Pie with filling can be made 2 days ahead; cover and refrigerate.