Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a mixing bowl, whisk together the flour, baking soda, cream of tartar, salt, cinnamon, and nutmeg.

In another bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.

Mix in the pumpkin puree, egg, and vanilla extract until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Using a cookie scoop, drop dough onto the prepared baking sheet, spacing them about 2 inches apart.

In a small bowl, mix together the granulated sugar and cinnamon for the coating.

Roll each cookie dough ball in the cinnamon sugar mixture before baking.

Bake in the preheated oven for 10-12 minutes, or until the edges are set but the centers are still soft.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.