Preheat oven to 350˚ F. Line two baking sheets with parchment paper. Set aside.
In a medium saucepan over medium-high heat, melt the butter and let it slightly brown.Remove from the heat and carefully pour the butter into a large heat-safe bowl. Use a spatula to scrape down the bottom of the pan to get all the brown butter bits. Set the butter aside to cool for about 30 minutes.
Meanwhile, in a medium bowl, whisk together the flour, baking soda, salt, cinnamon, and pumpkin spice and set aside.
To the butter, add both sugars, egg white, vanilla and pumpkin puree. Whisk until smooth.
Add the dry ingredients to the wet and mix until just combined. Do not over mix.
Fold in the dark chocolate chunks or chips.
Scoop the dough into 2 ounce portions and place 2 inches apart on the prepared cookie sheets.
Bake for 8 to 10 minutes or until the edges are set and golden brown but the center is still slightly under baked. Remove the cookie sheet from the oven and let cool for 10 minutes before transferring to a wire rack to cool completely. ENJOY!