Make the crust:
In the bowl of a food processor pulse the flour, granulated sugar, and salt until incorporated. Add the butter and pulse until the mixture is mealy and pea-sized lumps of dough remain, 20-25 pulses. Add 4 tablespoons of the water and pulse the dough, then add the remaining tablespoons of water, 1 tablespoon at a time while pulsing in between until the dough just comes together and small pieces of butter are still visible, being careful not to overwork the dough. Divide the dough in half and form into two 5-x-1 inch disks. Wrap each disk in plastic and chill at least 30 minutes before using. (If only using one crust, refrigerate the second one for up to 48 hours or freeze, tightly sealed, for 3 months.)
Make the filling:
Place the apples, lemon juice and zest, brown sugar, 1 teaspoon of the pumpkin spice, and the salt in a 9-inch skillet, bring to a boil, cook on medium high heat until small bubbles form, reduce the heat to medium-low and cook, stirring, until the appease release their water and caramelize slightly, 10 minutes. Transfer to a bowl to cool for 10 minutes. In another bowl whisk together the canned pumpkin, cream, the ½ cup light brown sugar, ⅓ cup granulated sugar, ¼ teaspoon salt, 2 of the eggs, vanilla, and the remaining tablespoon pumpkin spice.
Preheat the oven to 425°F. Remove one disc of dough from the refrigerator. Using a rolling pin, roll it out on a lightly floured surface until it is roughly 12 inches in diameter, keeping the dough as circular as possible. Fit the crust into a 9-inch pie plate, trimming it to leave a ½ inch overhang. Place the pie plate fitted with the dough in the fridge to chill for 15 minutes. Remove the chilled crust from the refrigerator and spoon the apple mixture evenly over the bottom. Pour the pumpkin mixture over the apples. Arrange the remaining dough on a lightly floured surface until it is roughly 12 inches in diameter, keeping it as round as possible. Using a pastry wheel or sharp paring knife, cut the dough into 12 ½-inch inch wide strips.
Arrange 6 parallel strips of the pie dough on top of the pie, leaving 1/2 inch space between them; fold back every other strip to your right, leaving about 3 inches of each strip on top of the pie. Arrange one of the long strips of dough strips perpendicular to the folded over edge of the folded strips. then unfold the folded strips over the perpendicular strip. Using the parallel strips underneath the perpendicular strip, and fold them back over the perpendicular strip. Arrange a second perpendicular strip. Unfold the folded parallel strips over the second strip. Keep going with the remaining strips until the pie is covered in a lattice. Trim the edges of the strips, leaving 1/2 inch hanging over the sides. Fold back the shell over the edge of the lattice strips, and crimp to seal. Beat the remaining egg in a small bowl and use it to brush the pie with egg wash. Sprinkle with the sanding sugar.
Bake the pie for 15 minutes at 425°F, reduce the temperature to 350°F, then continue to bake until the pumpkin filling has darkened and turned glossy and the crust is a deep golden brown, an additional 30-35 minutes. Cool on a rack for at least two hours before serving. Serve with whipped cream or vanilla ice cream.
