Start by adding all of the pie crust ingredients to the bowl of a food processor, except for the egg, and pulse until a crumb forms. Next, add the egg and pulse until a dough forms and starts to pull away from the edges of the bowl.
Gather the dough into a loose ball and wrap in plastic then chill in the refrigerator for at least 20 minutes or up to 2 days if you want to make it in advance.
While the dough is chilling, preheat the oven to 375°F.
Gently press the dough into the bottom and sides of a 9" pie dish. It’s okay if the dough breaks, this is normal. Gently push the dough back together to smooth and cracks. You can't overwork this dough.
Pierce the dough with a fork a few times to it doesn’t puff up while baking. Bake the pie crust in the preheated oven for 10 minutes until the bottom is set. Remove and allow to cool for 5-10 minutes.
While the crust is baking, make the filling. In a large bowl, whisk together the pumpkin, coconut milk, maple syrup, vanilla extract, pumpkin pie spice and salt. Whisk in the eggs and egg yolk one at a time, being careful not to overmix.
Pour the filling into the partially baked pie crust. Cover the crust only with aluminum foil or a pie shield, and bake again for 55-65 minutes or until the center of the pie is set.
Allow to cool completely at room temperature. Once cooled, serve or keep in the refrigerator for up to 2 days. Serve with coconut whipped cream and a sprinkle of cinnamon if desired!