Dice the butter and return it to the refrigerator while you prepare the flour mixture. Place the flour, salt, and sugar in the bowl of a food processor fitted with a steel blade and pulse a few times to mix. Add the butter and shortening. Pulse 8 to 12 times, until the butter is the size of peas. With the machine running, pour the ice water down the feed tube and pulse the machine until the dough begins to form a ball. Dump out on a floured board and roll into a ball. Wrap in plastic wrap and refrigerate for 30 minutes.
Cut the dough in half. Roll each piece on a well-floured board into a circle, rolling from the center to the edge, turning and flouring the dough to make sure it doesn't stick to the board. Fold the dough in half, place in a pie pan, and unfold to fit the pan. Repeat with the top crust.
Preheat the oven to 375°
Puree the chickpeas in a blender or a food processor until they are creamy and smooth. There shouldn’t be any pieces of the beans visible.
Pour the chickpeas into a large bowl.
Mix the baking powder and apple sauce to a medium bowl and mix until it’s frothy and light. Add to the chickpeas.
Add the pumpkin, milk, cornstarch, sugar, and spices to the chickpea mixture and whisk until smooth and completely combined. There shouldn’t be any lumps in the mixture.
Pour into the pie pan and bake for 20 to 30 minutes until the edges of the pie crust are golden brown. Turn the heat down to 350° and bake for another 25 to 30 minutes or until you can insert a sharp knife in the edge of the pie and it comes out clean. The center will be a little jiggly. That’s normal, it will set as it cools.
Do not slice until the pie has been refrigerated for at least 12 hours. Store in an airtight container in a refrigerator for up to 3 days. You can freeze it for up to 6 months.
*You could use the light version of coconut milk, or almond or soy milk, but only add one cup and then slowly add more if the mix is too thick. It should be pourable, just not runny.