Prepare the Crust

1. Chill your butter or shortening. If you’re using butter it’s probably already in the refrigerator.
2. Take eggs out of the refrigerator and let come to room temperature.
3. Mix the dry ingredients together: Sift almond flour, coconut flour, tapioca flour together into a food processor or bowl. This gets rid of any lumps. Add the maple sugar and salt.
4. Cut in the butter. Add the butter or shortening and pulse, 10-15 pulses. until it resembles coarse meal (see photos above). Alternately use a pastry cutter, or two forks, cut the butter into the dry ingredients until it resembles coarse meal. You’re looking for pea-sized bits of flour-coated butter. A few larger bits of butter is OK. In this step, you’re only breaking up the cold fat into tiny little flour-coated pieces; you’re not completely incorporating it. Do not overwork the ingredients.
5. Add the egg and pulse or mix just until the dough begins to form, 10-15 pulses, there may be stray crumbs, that’s ok.
6. Transfer the dough to a piece of parchment lightly floured with tapioca flour. Using your hands, gently bring the dough mixture together into a ball. Avoid overworking the dough. If it feels too dry or is too crumbly to form a ball, dip your fingers in cold water and then continue bringing the dough together. If it feels too sticky, sprinkle on a little more tapioca flour and continue bringing it together. Gather the dough into a ball.
7. Divide the dough in half using a sharp knife. Using your hands gently flatten each half into a 1-inch-thick disc. Wrap separately in plastic, then chill for at least 45 minutes. You can make the dough up to 5 days in advance.

Make The Filling

8. Mix the apples: In a large bowl, stir the apple slices, sugar, flour, lemon juice, cinnamon, allspice, and nutmeg together until thoroughly combined. 
9. Optional pre-cook: Pour the apple filling into a large skillet. Cook over medium heat, stirring gently, until the apples begin to soften, about 5 minutes. This step is optional, but I’ve found it makes for a juicier, more flavorful filling because it helps begin to soften the apples. If you can, take the few extra minutes to do this.
10. Remove from heat and set aside to slightly cool while you roll out the bottom crust.
11. Preheat your oven to 425° F and have a 9” glass pie dish ready
12. Roll out the bottom crust: . Roll out one of the discs of chilled dough on a sheet of parchment paper, dusted with tapioca flour (see tips above). Keep rolling until you have a circle 12 inches in diameter. 

13. Roll out the top crust into another 11-12” circle.

14. Spoon the filling into the crust. It’s OK if it’s still warm from the precooking step. It will seem like a lot of apples; that’s OK. Pile them tightly together.

15. Crimp the edges with your fingers or seal the edges with a fork. OPTIONAL, brush with milk and sprinkle with maple sugar. The milk and sugar help the crust brown nicely
16. Bake the pie on the middle oven rack for 25 minutes. After 25 minutes reduce the oven temperature to 375°F (190°C). Add a pie crust shield(see this video for a homemade shield) to prevent the edges from over-browning.
17. Continue baking until the pie is golden brown, and filling is bubbly, 35-45 more minutes. If the pie is getting too brown towards the end of bake time, tent an entire piece of foil on top of the pie. Note: If you want to be precise, the internal temperature of the filling taken with an instant-read thermometer should be around 190°F when done.
18. Allow the pie to cool at least 45 mins before serving. You can allow the pie to sit out at room temp, loosely covered, overnight if necessary.
19. The pie is best served within 24 hours of baking. If keeping longer cover and refrigerate until ready to serve, then gently warm in the oven.