Preheat oven to 375° F. Roll pie dough out and lay in a 9-inch pie pan. Poke the dough with a fork so it does not puff up. Place a piece of parchment paper over the top, and then place pie weights or dried beans in the center. Bake for about 20 minutes, or until it's a light golden brown and cooked all the way through. Remove pie weights, and let the crust cool.

To make the caramel, combine the sugar, water, and salt over medium heat. Stir until it comes to a boil. Simmer until it becomes honey-colored. Continue cooking, swirling the pan until it turns a dark amber brown. Add the cream, and reduce the heat to medium-low. Stir constantly until a candy thermometer reaches 225° F. Remove the pan from the heat. Add butter and vanilla. Stir in macadamia nuts, and transfer it to a heat-proof container.

For the filling, heat the coconut milk and whole milk over medium heat until it gently simmers. Meanwhile, combine the egg yolks, sugar, and cornstarch. Whisking constantly, temper the egg mixture with some of the milk mixture. Add the egg mixture into the milk, whisking the whole time. Cook over medium heat, stirring constantly, until the mixture is thickened. Remove from heat. Add the butter, salt, and vanilla. Immediately strain the mixture over a fine-mesh strainer, discarding of any lumps. Add the coconut flakes and cool.

To assemble, pour caramel mixture over the pie crust. You may not use all of it. I usually do in mine. Pour the filling mixture over the top of the caramel. Spread with whipped cream, and top with toasted coconut flakes.