Preheat the Oven: Start by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper.

Mix Wet Ingredients: In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until smooth. Then, add the pumpkin puree, egg, and vanilla extract. Mix well until fully incorporated.

Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, cream of tartar, salt, cinnamon, and nutmeg.

Combine Both Mixtures: Gradually add the dry ingredients to the wet mixture, stirring until the dough comes together.

Prepare Sugar Mixture: In a small bowl, mix the granulated sugar and cinnamon for rolling.

Shape Cookies: Using a cookie scoop or tablespoon, scoop out dough and roll into balls. Roll each ball in the cinnamon sugar mixture until fully coated.

Bake Cookies: Place the rolled cookie dough onto the prepared baking sheet, spacing them a couple of inches apart. Bake for 10-12 minutes until the edges are lightly golden.

Cool Off: Remove from the oven and allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.