In a medium saucepan over medium heat, melt the unsalted butter. Continue cooking until it foams and turns a golden-brown color, about 2-3 minutes, releasing a nutty aroma. Remove from heat and let it cool.

In a large mixing bowl, whisk together the cooled brown butter, light brown sugar, white sugar, maple syrup, and egg yolk until smooth. Then, add vanilla extract and pumpkin puree, mixing well.

In a separate bowl, combine all-purpose flour, baking soda, baking powder, kosher salt, pumpkin pie spice, and ground cinnamon. Stir until well mixed.

Gently fold the dry ingredients into the wet ingredients until just combined. Cover the dough with plastic wrap and chill in the refrigerator for about 30 minutes.

Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.

Once the dough has chilled, use a cookie scoop to portion out the dough. Roll each scoop into a ball and place them on the baking sheets, spacing them about 3 inches apart.

Bake the cookies for 10-14 minutes until the edges are set and centers are slightly underbaked. Allow cooling on the baking sheets for a few minutes before transferring to wire racks.