In a medium saucepan over medium heat, melt unsalted butter, stirring continuously. Watch as the butter foams and then turns a beautiful amber color, which should take about 5–7 minutes. Remove from heat and let the brown butter cool for about 20 minutes.

While the brown butter cools, preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

In a medium bowl, whisk together all-purpose flour, baking soda, baking powder, salt, pumpkin pie spice, and cinnamon. Mix until thorough, ensuring there are no lumps.

In a large bowl, combine the cooled brown butter and dark brown sugar. Whisk these together until the mixture is clumpy. Add in the egg yolk, maple syrup, and pumpkin puree, stirring until the mixture is smooth.

Gently fold the reserved dry ingredients into the wet mixture using a spatula. Be careful not to overmix; stop stirring once you see no dry flour.

Using a cookie scoop, portion out dough balls (approximately 2 oz each) and roll them in a cinnamon-sugar mixture for added flavor. Place the dough balls on the prepared baking sheet.

Slide the baking sheet into the preheated oven and bake for 12–15 minutes. Keep an eye on the cookies, as you'll know they’re done when the edges are darkened and the centers look slightly puffy.

Once baked, remove the cookies from the oven and allow them to cool on the baking sheet for about 5 minutes. Then transfer to a cooling rack to cool completely.