Line a small bowl with a paper towel and pour ¼ cup of canned pumpkin. Cover the pumpkin with the paper towel.
Preheat the oven to 350 degrees. Line a baking sheet with parchment paper.
Using a stand mixer with a paddle attachment (or a bowl and handheld mixer) beat the room temperature butter with the ¾ cup of sugar until fluffy, about 2 minutes.
Add the vanilla extract, egg, pumpkin puree and mix until combined.
In a separate bowl, whisk together the flour, cream of tartar, baking powder, cinnamon, nutmeg and salt.
With the mixer on low, slowly add the dry ingredients until fully combined.
In a small bowl, add the ¼ cup of sugar to roll the cookies in.
Using a small cookie dough scooper or a spoon, drop about a tablespoon of the cookie dough into the sugar. Roll it around and place it on the baking sheet.
Bake for 12-14 minutes until light golden.
Cookies are best stored in an airtight container for up to 5 days.