Melt a stick of butter in a pan over medium heat. Once the butter has completely melted and begins to lightly bubble, begin to swirl the pan. Continue to swirl the pan while the butter cooks. The butter will foam and then, as the foam subsides, the milk solids in the butter will begin to turn a golden brown color. Once the milk solids are golden brown and smells distinctly buttery and nutty, immediately remove the butter from the heat and pour the butter into a heat prove bowl. Allow the butter to cool to room temperature before preparing the dough.
Using paper towels, remove any excess liquid from the pumpkin puree. You don't want any pools of liquid in your puree or it will change the consistency of your cookies.
In a mixing bowl, combine cooled brown butter, dried pumpkin puree, brown sugar, egg yolk, maple syrup and vanilla. Whisk until all the wet ingredients are homogenous.
Next, in a second mixing bowl, add flour, baking soda, cinnamon, pumpkin pie spice and salt. Mix together the dry ingredients so the spices and baking soda are evenly distributed throughout the flour.
Gently fold the dry ingredients into the wet ingredients with a spatula just until combined. Cover the mixing bowl with plastic wrap and refrigerate the dough for at least two hours or up to overnight.
When you are ready to bake the cookies, preheat the oven to 350°F and line two baking sheets with parchment paper. On a small plate, combine 1 1/2 tablespoons of sugar and 1 teaspoon of cinnamon. Scoop cookie dough using a greased two tablespoon cookie scoop. Roll the dough into a ball and roll in the cinnamon sugar mixture. Place dough balls onto the parchment lined baking sheets. Bake the cookies at 350°F for 5 minutes.
Allow cookies to cool for a few minutes before transferring to a wire rack to cool completely.