Preheat the oven to 375°F/190°C. Line 2 baking sheets with parchment paper. Make sure the oven rack is in the center of the oven.
Mix the wet ingredients. In a large mixing bowl with a hand mixer, or in a stand mixer with the paddle attachment, cream together the softened vegan butter with the powdered sugar and the brown sugar. When it is light and fluffy, add the pumpkin and the vanilla. Mix again until incorporated.
Add the dry ingredients. Add the all purpose flour, cream of tartar, pumpkin pie spice, baking soda, and salt. Mix on low speed until the cookie dough has formed. It is soft and delicate so don't over mix this dough.
Shape the cookies. Using a one tablespoon cookie scoop, portion out the individual cookie dough balls. Roll each one in the cinnamon sugar before placing on the prepared cookie trays.
Bake. Bake a single cookie tray for 11 to 13 minutes, depending on your oven. For an almost underdone cookie, go for 11 minutes, for a good cookie, aim more towards 13 minutes. Let them cool on the hot cookie trays for 15 minutes before removing to finish cooling on wire racks. Serve and enjoy!
