Preheat oven to 350℉ (177℃)
Prepare 2 baking sheet pans by lining with parchment paper or silicone baking mats.
Combine flour, baking soda, pumpkin spice and salt in a medium-sized bowl. Whisk together until well combined. Set aside for later.
1¼ Cups All-purpose flour, ½ teaspoon Baking soda, ½ teaspoon Salt, 2 teaspoons Pumpkin pie spice
Place pumpkin puree on a plate. Blot well with paper towels to remove excess moisture. Set aside for later.
⅓ Cup Pumpkin puree
Add granulated sugar and brown sugar to bowl with cooled brown butter.  Whisk until well combined. 
½ Cup Brown sugar, ½ Cup Granulated sugar
Add egg and pumpkin puree to mixing bowl.  Whisk vigorously until well combined. 
1 Large Egg
Add dry ingredients (flour, etc..) to mixing bowl. Using a silicone spatula, stir until everything is mixed together and you don’t see any dry spots.
Cover the mixing bowl with a kitchen towel and place in the refrigerator for 30 minutes. This helps the dough firm up and lets the flavors blend together.
Scoop approximately 1½ tablespoons of cookie dough onto prepared baking sheets. Leave at least 2" of space between each cookie to allow for spreading.
Bake cookies for 10 - 12 minutes. Edges will be slightly browned and center of cookie will have risen slightly.
Allow cookies to cool on baking sheets for 10 minutes, then transfer to a wire rack to cool completely.