Preheat oven to 350 degrees F.
Line two 12-cup muffin tins with paper liners. Set aside.
In a large bowl, whisk together the pumpkin, sourdough starter, granulated sugar, oil, eggs and vanilla until well-combined.
Add the flour, cinnamon, baking powder, baking soda, salt and chocolate chips (if using) and mix until just combined and no dry streaks remain. Don’t over mix.
Scoop the batter into the prepared muffin tins, filling the muffin cups 1/2 to 2/3 full. If desired, sprinkle a few regular or mini chocolate chips on top of the muffins.
Bake for 15-20 minutes until the tops spring back lightly to the touch and/or a toothpick comes out clean or with a few moist crumbs.
