Preheat your oven to 350°F (175°C).

In a food processor, pulse the graham cracker crumbs and macadamia nuts together until the nuts are finely ground.

Transfer the crumb mixture to a bowl and stir in the granulated sugar and melted butter until well combined.

Press the mixture firmly into the bottom and up the sides of a 9-inch pie dish. Bake for 10 minutes, then remove and let cool slightly.

In a medium bowl, whisk the egg yolks and lime zest together for about 2 minutes until the mixture thickens slightly.

Add the sweetened condensed milk and Key lime juice to the yolks, whisking until smooth and fully combined.

Pour the filling into the baked crust and return the pie to the oven.

Bake for 15 minutes, or until the filling is set but still slightly jiggly in the very center. Do not brown the top.

Cool the pie to room temperature on a wire rack, then refrigerate for at least 3 hours or overnight to fully set.

Before serving, whip the heavy cream and powdered sugar in a bowl until stiff peaks form.

Spread the whipped cream over the chilled pie and garnish generously with the toasted coconut flakes.