In a large mixing bowl, gently combine all of the filling ingredients.
While the tapioca soaks up the peach juices, preheat the oven to 350F and prepare your crust.
In a food processor (using the S-blade), pulse the almond flour, coconut flour, sugar and salt a few times.
Add butter and pulse until the butter chunks are about the size of peas.
Turn the processor on and pour your milk and egg white in while blending. Keep blending until a dough ball forms.
Place the dough onto a baking sheet covered with parchment paper and roll it out into a circle ¼ inch thick.
Add your filling in the center, arranging your peaches as desired. Leave a margin of 2 inches all the way around.
Use the parchment paper to fold the edges over the filling to form a crust, rotating as you go.
Whisk together an egg and milk to make the egg wash. Coat the crust only and sprinkle with sugar.
Bake for 40-50 minutes until the dough turns beautifully golden.
Let cool before serving.