Preheat oven: Set the temperature to 350°F and prepare two baking sheets with parchment paper now.
Cream butter and sugar: Beat softened butter with brown sugar until a light and fluffy mixture forms.
Add wet ingredients: Mix in pumpkin puree, egg, and vanilla extract until completely smooth and combined.
Whisk dry ingredients: Combine flour, cocoa powder, baking soda, and salt in a separate large bowl.
Combine mixtures: Gradually stir dry ingredients into the wet mixture until just combined without any overmixing.
Add chocolate chips: Fold in chocolate chips gently, distributing them evenly throughout the cookie dough.
Scoop dough: Drop rounded tablespoons onto prepared sheets, spacing them about two inches apart for spreading.
Bake cookies: Place in preheated oven and bake for 10-12 minutes until edges are set.
Cool properly: Let cookies rest on the baking sheet for five minutes before moving to a rack.
Serve and enjoy: Wait until completely cool, then serve these delicious double chocolate pumpkin treats IMMEDIATELY!