Preheat the oven to 350°F (175°C) and line a muffin pan with liners.
In a large mixing bowl, combine the pumpkin puree, granulated sugar, brown sugar, and vegetable oil.
Add the eggs and vanilla extract to the mixture and stir until well combined.
In another bowl, whisk together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt.
Gradually fold the dry ingredients into the wet mixture until just combined.
If desired, fold in the chocolate chips for added richness.
Scoop the batter into the prepared muffin pan, filling each liner about 3/4 full.
Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean.
Remove from the oven, let cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
