5 cups sweetened flaked coconut
7 tablespoons unsalted butter
1/2 cup chocolate chips
2 large eggs
1/2 cup sugar
1/4 cup all-purpose flour
1/2 teaspoon vanilla extract
2 cups whole milk
3/4 cup heavy cream
Additional sweetened flaked coconut, toasted, optional
Preheat oven to 350ºF. Mist a 9-inch pie plate with cooking spray. Place 3 cups coconut in a bowl. In a pan, melt 5 Tbsp. butter. Stir butter into coconut until moistened. Press mixture into bottom and sides of pie plate. Bake until crust is deep golden brown, 25 to 30 minutes. Check often—if edges are browning before bottom, cover edges with strips of foil. Transfer crust to a wire rack. Sprinkle chocolate chips over hot crust and let stand for 5 minutes, until melted. Gently spread chocolate over bottom of crust. Refrigerate crust for 10 to 15 minutes.
In a bowl, whisk eggs, sugar, flour and vanilla until smooth. Warm milk in a pan over medium heat until nearly simmering. Whisking constantly, slowly pour hot milk into egg mixture. Return milk mixture to pan. Cook over low heat, stirring constantly, until mixture begins to boil and thickens enough to coat back of a spoon, about 5 minutes. Remove from heat, stir in remaining 2 cups coconut and 2 Tbsp. butter; let stand 10 minutes, stirring occasionally. Pour custard into crust. Cover with plastic wrap, pressing directly against surface of custard, and chill completely, about 1 1/2 hours.
Using an electric mixer, beat cream until stiff peaks form. Spread whipped cream over custard, swirling decoratively. Chill pie for 30 minutes. Sprinkle with toasted coconut before serving, if desired.