Preheat your oven to 350°F (175°C) and lightly grease a 9-inch pie dish. In a medium bowl, combine the graham cracker crumbs, granulated sugar, and melted butter until the mixture resembles wet sand.

Press the crumb mixture firmly into the bottom and up the sides of the prepared pie dish. Bake for 10 minutes until lightly golden and fragrant, then set aside to cool slightly while you make the filling.

In a large mixing bowl, whisk the egg yolks until they are pale and slightly thickened, about 2 minutes. Gradually whisk in the sweetened condensed milk and cream of coconut until completely smooth and well combined.

Stir in the fresh Key lime juice and lime zest, mixing gently just until the filling thickens naturally from the acidity of the citrus. Pour the creamy mixture into the pre-baked graham cracker crust, spreading it into an even layer.

Bake the pie at 350°F (175°C) for 15 minutes, or until the edges are set but the center still has a slight jiggle. Remove from the oven and allow it to cool completely on a wire rack for about 1 hour.

Once at room temperature, transfer the pie to the refrigerator and chill for at least 3 hours to ensure it sets completely. Before serving, whip the heavy cream to soft peaks, spoon it over individual slices, and sprinkle with toasted coconut flakes for a beautiful presentation.