TO MAKE BROWN BUTTER. Place the butter in a light-colored pan and melt it over medium-high heat. Once it melts and starts to sizzle, begin stirring occasionally. This process will take a few minutes. As it melts, the milk solids will start to separate — keep stirring so they don’t burn. The butter will gradually turn a darker color. When you smell a nutty aroma and the butter reaches a deep golden brown, it’s done. Remove it from the heat and let it cool to room temperature for about 30 minutes, or until it reaches 72°F (22°C).

PREHEAT THE OVEN AND PREPARE THE BAKING PANIn the meantime, line 2 baking sheets with parchment paper or a silicone baking mat and set them aside. Preheat the oven to 350°F (180°C).

PREPARING THE DRY INGREDIENTSIn a medium-sized bowl, combine the sifted flour, cinnamon, nutmeg, ginger, baking soda, cream of tartar, and salt.

MIXING THE WET INGREDIENTSIn a separate large bowl, whisk together the cooled brown butter, granulated sugar, and brown sugar (or use a hand mixer on medium speed) until well combined. Add the pumpkin purée, egg yolks, and vanilla and mix until fully incorporated.

COMBINING DRY AND WET INGREDIENTSAdd the dry ingredients to the wet ingredients and fold together with a spatula until just combined. Do not overmix

CINNAMON-SUGAR MIXTUREIn a small bowl, combine ⅓ cup granulated sugar and 1 ¼ teaspoons cinnamon.

SHAPING AND COATINGScoop the dough using a 2-tablespoon cookie scoop. Roll each ball in the cinnamon-sugar mixture. Place the cookies on the prepared baking sheets about 2 inches apart.

BAKINGBake for 9–11 minutes, or until the edges are set but the centers remain soft and slightly underbaked.

COOLINGLet the cookies cool on the baking sheet for 10 minutes, then transfer them to a wire rack to cool completely.