In a medium, microwave safe bowl, melt the butter. Let cool slightly, then briskly whisk in the granulated sugar and brown sugar, until no brown sugar lumps remain. Whisk in the pumpkin and vanilla extract until smooth. Set aside.
In a large mixing bowl, whisk together the whole wheat pastry flour, cream of tartar, baking soda, baking powder, salt, cinnamon, ginger, nutmeg, and all spice. Make a well in the center of the dry ingredients, then add the wet ingredients all at once. With a wooden spoon or rubber spatula, stir by hand, just until the flour disappears. Cover the bowl with plastic wrap, then let chill for at least 30 minutes or up to 3 days.
When ready to bake, preheat the oven to 350 degrees F and line two baking sheets with parchment paper or silpat mats. In a shallow dish or bowl, stir together the 1/4 cup granulated sugar and 1/2 teaspoon cinnamon for rolling.
With a cookie scoop or spoon, portion the dough by 1 1/2 tablespoons and roll into balls. Roll the dough in the cinnamon and sugar mixture to coat, then arrange on the prepared baking sheet. Flatten the balls slightly (the cookies only spread a little bit as they bake). Bake for 9-11 minutes, until the edges are barely golden (the cookies will look underdone). Place the baking sheets on a wire rack and let cool 10 minutes, then remove the cookies to a wire rack and let cool completely.
Store leftover cookies in an airtight container at room temperature for up to 1 week or freeze for up to 3 months.
Unbaked cookie dough balls can be frozen for 3 months in a ziptop bag with all of the air squeezed out. Arrange the dough balls on a baking sheet and bake directly from frozen.
To make the dough ahead, prepare it up to the point of baking, then store it in the refrigerator for up to 3 days.