Add your coconut milk, salt and heavy cream to a pot and bring to a simmer on medium low heat.
In a bowl, whisk your eggs, egg yolk and sweetener until well combined.
Temper the eggs by slowing adding a large spoonful or 1/4 cup of the hot milk to the egg mixture and whisk constantly to avoid cooking the eggs. Repeat until you have added all the milk to the egg mixture.
Add your egg mixture back to the pot and simmer on medium low heat for about 5 minutes. Stir constantly until it thickens or coats the back of your spoon.
Sprinkle in your xanthan gum and whisk briskly until well combined.
Remove from heat and add your butter, vanilla, and shredded coconut.
Cool your filling, stirring periodically to avoid a skin from forming on the surface.
Once cooled, add your filling to your crust.
Cover with plastic wrap, store in an airtight container, and refrigerate for at least 3 hours.