Preheat your oven to 350°F and line a large baking sheet with parchment paper.
In a small saucepan over medium heat, melt the butter, swirling continuously until it turns golden brown and smells nutty; remove from heat to cool.
Combine 2 tablespoons of sugar and 1 teaspoon of cinnamon in a small bowl for the coating.
Place pumpkin puree on a thick stack of paper towels and squeeze out as much moisture as possible until the pumpkin is quite dry.
In a mixing bowl, whisk together the browned butter, sugars, egg yolk, and vanilla until smooth.
Fold in the blotted pumpkin puree.
Stir in the flour, baking soda, cream of tartar, salt, and spices until a soft dough forms.
Scoop the dough into balls, roll each ball in the prepared cinnamon-sugar mixture, and place on the baking sheet.
Bake for 12 minutes or until the edges are set but the centers remain soft.
Allow the cookies to cool on the pan for 5 minutes before transferring to a wire rack.