Grind graham crackers to fine crumbs in a food processor. Measure out 2 ½ cups graham crumbs and place the crumbs back into the food processor. Add 6 Tablespoons unsalted butter, ¼ cup granulated sugar, and ⅛ teaspoon salt. Process until evenly mixed ( the mixture will look like wet sand).
Press the graham mixture into 9-10" pie pan. Bake at 350 for 10 minutes, until fragrant. Set aside to cool.
Coconut Filling
Whisk together 5 large egg yolks and 5 Tablespoons cornstarch in a medium bowl. Set aside.
Add 1 can full-fat coconut milk, 1 can sweetened condensed milk, and ¼ teaspoon salt to a medium to large saucepan. Bring the mixture to a boil over medium-high heat while stirring very often. Reduce the heat to medium-low. Remove ½ cup of the coconut milk mixture and slowly pour it into the egg yolk mixture while whisking constantly.
Slowly pour the egg yolk mixture into the saucepan with the remaining coconut milk mixture while whisking constantly. The mixture will immediately start to thicken. Cook for an additional 2 minutes, whisking constantly. Remove the saucepan from the heat and stir in the 1 ½ cups frozen shredded coconut , 2 Tablespoons unsalted butter, and 1 teaspoon vanilla extract.
Pour the warm coconut filling into the prepared graham crust. Place plastic wrap directly onto the filling and refrigerate the pie to cool completely (at least 2 to 4 hours).
Whipped Cream Topping
Add 1 cup whipping cream, 1 Tablespoon granulated sugar, and ¼ teaspoon vanilla extract to a medium bowl. Whip the cream using a hand mixer at high speed until the cream holds soft peaks. Spread the whipped cream evenly over the coconut filling. Sprinkle the cream with toasted coconut if you wish. Serve the pie immediately.
Notes
Graham wafers can vary in size depending on which brand you choose. Instead of counting wafers, I strongly recommend measuring by weight or even measuring the crumbs by volume after processing them.