Preheat oven to 350 degrees F.

Make the crust.  In a large bowl, stir together flour, sugar, tapioca, vanilla bean seeds, and lime zest.  Work the coconut oil in until a dough is formed.

Press the dough into a 9 by 13 inch pan and bake 20-25 minutes until golden brown.

While the dough bakes, make the filling.  In a medium saucepan, stir together sugar, eggs, egg yolk, lime juice, lime zest, and coconut flour until combined.  Put the vanilla bean pod in the pot, it still has lots of good flavor in it.  Place over medium low heat and bring to a gentle boil, whisking constantly.  Cook for about 5 minutes until thickened.

Remove from the heat and stir in the coconut butter.  If there are lumps, strain through a fine mesh sieve.  If there aren’t lumps, go ahead and just pour it into the baked crust.

Return the pan to the oven and bake for 15 minutes until mostly set.  Cool completely to room temperature before covering and refrigerating overnight until fully chilled.  Cut into bars and serve.  Bars may be stored in the refrigerator for up to 5 days or frozen, wrapped in parchment and foil and placed in a zipper bag for up to 3 months.  Thaw in the refrigerator overnight.