In a small dish, lightly beat the three egg yolks. Set aside.
In a medium saucepan, whisk together the coconut sugar, tapioca flour, salt, coconut milk, and coconut milk beverage over medium heat. Whisk constantly.
Add the butter. Bring the mixture to a boil, whisking constantly. Allow the mixture to boil for 1 minute. It should begin to thicken.
Remove the mixture from the heat. Spoon 1 tablespoon of the pudding mixture into the egg yolks and stir vigorously. Spoon in 1 more tablespoon and stir vigorously again.
Slowly pour the egg yolk mixture into the pudding mixture whisking vigorously and constantly. This is to keep the hot pudding mixture from cooking the egg yolks.
Once the egg yolks are whisked in, add the vanilla extract. Return the pudding mixture to the stove top and heat over medium heat.
Bring the mixture back to a boil and boil for 1 minute, whisking constantly.
Pour the mixture into the pre-baked pie crust. Place the pie in the fridge and allow it to set up for at least 4 hours.
Cut and serve! Store leftovers in the fridge.