Combine wet ingredients: in a large mixing bowl combine squash mixture, egg, melted butter, vanilla extract, sourdough discard, and maple syrup.
Combine dry ingredients: add flour, salt, and baking soda to a large nonmetallic bowl and combine well.
Add wet mixture to dry mixture and roughly combine with a wooden spoon or rubber spatula, then use an electric mixer or stand mixer to thoroughly combine until the batter is smooth.
With a wooden spoon or rubber spatula, fold in chocolate chips.
Ensuring batter is in a nonmetallic bowl, cover securely and let it ferment at room temperature for 4-6 hours. (If it is cold in your home set it in a warm place between 70-75 degrees).
After fermenting on the countertop, the top of the batter may be slightly discolored - don't worry, it won't affect the the bread.
Pour batter into into a standard bread loaf pan lined with parchment paper or butter.
Preheat oven to 350 degrees Fahrenheit.
Bake on the center rack for 55-60 minutes, or until a toothpick comes out clean when inserted into the center.
Let bread cool in the pan for 30 minutes before slicing.
Enjoy with butter, and if you want extra sweetness add some coconut sugar on top!