Preheat your oven to 350°F (175°C). In a mixing bowl, combine the graham cracker crumbs, melted butter, and ⅓ cup sugar. Mix until well combined, then press this mixture firmly into the bottom and up the sides of a 9-inch pie dish. Bake for 10 minutes until golden and aromatic. Remove from the oven and allow the crust to cool completely.

In a medium saucepan, whisk together ½ cup sugar, cornstarch, and salt until evenly distributed. Gradually whisk in the 2 ½ cups of milk, ensuring there are no lumps. Cook over medium heat, stirring constantly for about 5-7 minutes, until the mixture thickens and starts to bubble.

In a separate bowl, lightly beat the 4 egg yolks. Gradually add a few spoonfuls of the hot custard mixture to the yolks while whisking constantly. Once combined, return this egg mixture to the saucepan and cook for an additional 2-3 minutes, stirring until thickened and bubbling again.

Remove the saucepan from heat and stir in the 1 teaspoon of vanilla extract and 1 cup of sweetened shredded coconut. Allow the coconut custard to cool slightly before pouring it into your cooled graham cracker crust.

Cover the pie with plastic wrap, ensuring it touches the surface to prevent a skin from forming. Chill in the refrigerator for at least 4 hours, or ideally overnight.

In a mixing bowl, pour in 1 cup of heavy whipping cream along with 2 tablespoons of powdered sugar. Using an electric mixer, whip the cream on medium-high speed until soft peaks form, about 3-5 minutes.

Once the pie has chilled and set, spread the whipped cream over the top. Toast the ½ cup of coconut flakes in a dry skillet over medium heat for about 3-5 minutes until golden brown. Sprinkle the toasted coconut over the whipped topping just before serving.