1. In a medium pot, whisk together corn starch and milk until completely smooth. Add sugar and salt; whisk again to combine. Add egg yolks, coconut milk, and heavy cream; whisk again (mixture will be lumpy because of the fat in the coconut milk, that’s okay).
2. Set pot over medium high heat and, while whisking constantly, slowly bring mixture to a boil. Then immediately reduce heat to low and simmer, while whisking constantly, and cook for about 1-2 minutes, until pudding is thick and smooth. Remove pot from heat. Strain pudding through a fine-mesh strainer into a clean bowl.
3. While pudding is still warm, add vanilla extract, coconut flavor (if using), butter, and sweetened shredded coconut. Stir to combine.
4. Pour warm filling into fully-cooked, fully-cooled pie crust. Smooth top with a spatula. Place plastic wrap flush against the pudding surface (to prevent “pudding skin” from forming), then wrap the entire pie in plastic wrap, and refrigerate to cool completely, 3 to 4 hours.
5. To make whipped cream, add heavy whipping cream, Instant vanilla pudding powder (if using), and 2 Tablespoons sugar to the bowl. Whisk to combine. Beat until soft peaks form.
6. Just before serving, spoon whipped cream on top of pie. Garnish with sweetened shredded coconut, if desired, and serve.

Make-Ahead Tip: The filing can be made two days ahead. Store in a bowl in the refrigerator. Cover surface of filling with plastic wrap to prevent the skin from forming. The crust can also be made a day ahead. Cool completely and wrap in plastic overnight. You can also pour the filling in the pie crust the day before. Just be sure to use the plastic wrap on the surface, store in the refrigerator, and don’t add whipped cream until just before serving.