Prepare the brown butter about an hour before making the cookies. Melt butter in a clear, heavy-bottom saucepan. Once it starts to foam, whisk continuously until brown bits form. Pour into a clean bowl and cool for 30 minutes to room temperature.
Blot the pumpkin puree by placing 2-3 paper towels across a shallow bowl. Scoop a generous 1/2 cup of pumpkin puree onto the paper towels, allowing the excess water to absorb. Before using, squeeze out the remaining water from the pumpkin.
Whisk together the flour, spice blend, baking soda, and salt in a separate bowl until well combined. Set aside.
In another bowl, stir the cooled brown butter, sugar, and maple syrup until well combined. Add the egg yolk, mixing until fully incorporated.
Mix in the blotted pumpkin, vanilla, and maple extracts until well combined.
Gradually stir the dry ingredients into the wet mixture until just combined. Cover the dough with plastic wrap and chill in the fridge for 8 hours or overnight.
When ready to bake, preheat the oven to 350°F and line 1-2 large cookie sheets with parchment paper. Remove the dough from the fridge and let it sit at room temperature for 30 minutes to allow for better spreading.
Prepare the spiced sugar by mixing the spice blend used in the cookie dough with granulated sugar until well combined. Adjust the balance of spices to taste.
Using a 2" cookie scoop, portion out the dough and roll each ball in the spiced sugar mixture. Place the coated dough balls about 2-3" apart on the prepared baking sheets.
Bake the cookies for 12-14 minutes. At the 9-10 minute mark, check the cookies. If they are puffier than desired, open the oven, lift the cookie sheet a few inches, and firmly bang it on the oven rack a few times. Continue baking for the remaining 3-4 minutes.
Allow the cookies to cool on the baking sheet, placed on top of a cooling rack, for 3-5 minutes. Then, transfer the cookies to the cooling rack to cool completely.