Preheat the oven to 350°F. Line muffin tins with paper muffin cups and set aside.
In a large mixing bowl, beat together the sourdough starter, mashed bananas, sugar, olive oil, and egg until the mixture is smooth.
In a a separate bowl whisk together the white whole wheat flour, baking soda, cinnamon, and salt. Add the dry ingredients to the wet mixture and fold together with a spatula until the dry ingredients are just incorporated. Fold in the chocolate chips.
Fill the prepared muffin tins with about 1/4 cup of the batter in each muffin cup.
Sprinkle raw sugar on top of the batter. Bake the muffins for 18 - 20 minutes, until a toothpick inserted in the center of the muffin comes out clean (or with a few wet crumbs).
Cool the muffins in the pan for about 10 minutes, then transfer to a wire rack to cool completely.