For the Crust

1. Cut the butter into cubes, about ½ inch thick. The butter should be very cold.
2. In a food processor, combine the flour and salt and butter and pulse gently to combine. The mixture should have dime-size pieces of butter.
3. Next, add the egg, vinegar, and 1 tablespoon water; pulse until the dough starts to form. Add additional water as needed.
4. Press the dough into a ball, flatten it into a disc, about 5 inches wide. Wrap in plastic wrap and refrigerate for a minimum of 45 minutes.

Apple Blueberry Filling

1. Remove one crust from the refrigerator. Roll the dough on a lightly floured surface, rolling from the center to the edges, and rotating occasionally. Roll it out to about 11 inches in diameter, leaving you at least 1 inch on each side of the pie plate. Place the crust in a 9-inch pie plate.
2. Peel and slice the apples about 1/8-inch thick and toss with the lemon juice. Then add the blueberries.
3. In a separate bowl, combine the dry ingredients and then toss the apples thoroughly in the dry ingredients. Finally, drizzle the maple syrup over top, then pour your apples into your prepared crust.

Make a Lattice Crust

1. Preheat the oven to 375°F.
2. Remove the second disc of dough from the fridge. Roll out the second crust 10-12 inches wide and at least 1/8-inch thick. Cut it into strips. Use the remaining dough to make small cut-out shapes if desired.
3. Place 3 strips horizontally and equally spaced across the pie. Fold back every other horizontal strip. Then lay one strip perpendicular (vertically) to the others across, and fold the horizontal strips back on top of it so they lay over top of the one you just laid down.
4. Next, fold up one center horizontal stripe and lay down another vertical stripe in the center. It’s best to use a long piece of dough for the center. Then fold the horizontal strip back down.
5. Repeat this process until all the strips have been used and the top of the pie is covered with the lattice crust.
6. Trim away excess edges of the dough strips. Then fold over the edges of the bottom crust on top on top of the lattice and press together, crimping the edges as you go. Place cut-out shapes around the outside edge if desired.
7. Lightly beat the egg and brush it over the top of all the pie dough. Sprinkle with coarse sanding sugar if desired.
8. Bake for 50-60 minutes until the apples reach a soft consistency. After 30 minutes of baking, place a silicone pie shield around the outside edge to prevent the crust from browning too quickly.
9. Cool for at least 2 hours before cutting.