Crust: In a food processor, pulse macadamia nuts until fine. Add cold cubed butter and flour; pulse again. Gradually add ice water until dough is crumbly. Form into a disk, wrap in plastic, and refrigerate 20-60 minutes. Roll out, fit into an 8″ pie dish, and bake at 350 F for about 15 mins.
Filling: Create a slurry with cornstarch and water. In a saucepan, whisk coconut cream, milk, and sugar. Simmer, then add coconut extract and slurry, cooking until thickened. Pour half the filling into the crust, mix chocolate into the remaining filling and add on top. Smooth with a spatula.
Topping: Whip heavy cream with sugar to stiff peaks. Toast coconut shavings in the oven at 350? for 5-7 mins. Cool pie completely and top with whipped cream and coconut.