In a large bowl combine the sugar, sourdough starter, and water. Stir with a fork.
In a separate bowl sift together the bread flour and cocoa powder and then add it to the liquid mixture. Mix everything until all the flour has absorbed the water.
Then, cover the bowl with plastic wrap and let it rest for 1 hour.
Add the salt & chocolate chips
After the dough has rested, add the salt and chocolate chips to the dough mixture. Fold everything in and work the dough into a smooth ball by repetitively folding it into itself.
Cover the dough and let it rest for 30 minutes.
Stretch and fold the dough
After the dough has rested, perform your first stretch and fold to strengthen the dough.
Gather a portion of the dough, lift it a few inches, and stretch it over to the opposite side. Rotate the bowl and do this to all 4 quadrants of the dough.
Once complete, cover the dough and let it rest for 30 minutes.
Perform 3 more stretch and folds in 30-minute increments totaling 4 stretch and folds.
Once complete, allow the dough to rest for the remaining bulk rise (10-12 hours) covered.
Shape the dough
The following morning, check the dough to make sure it has at least doubled in size. Remove the dough onto a lightly floured work surface and make a rough circle shape using your hand and bench scraper.
Sprinkle some flour over the surface and flip the dough over so the flour side is now on the work surface.
Using the envelope-style shaping method, fold the top of the dough to the center, the left side to the center, the right side over the left side, and the bottom of the dough to the center.
Flip the dough back over and tighten the shape using your hands. Gently push the dough towards yourself and make circular motions to tighten the seams.
Once the desired shape has been achieved, place the dough in a linen-lined lightly floured bowl seam side up and cover it with a towel for 1 hour.
Score & Bake
30 minutes before you get ready to bake, preheat your oven to 450 degrees F with the baking pan in the oven.
After the dough has rested for the full hour, invert the bowl onto a piece of parchment paper.
Optional: sift flour over the top of the dough (this is mainly for appearance).
Score the dough using a lame or sharp knife. Score 1 line down the middle, and cross it with a second line resembling a cross.
Place the dough in the pan using the parchment paper and decrease the oven to 425 degrees F. Bake covered for 20 minutes and uncovered for 25 minutes.
Allow the bread to cool for a minimum of 2 hours before slicing it.
Chocolate sourdough bread lasts 3-4 days on your counter in an airtight container or bread bag of your choice.
Notes
Baker's schedule: mix the dough the evening before approximately 7 PM to bake for the following morning. The dough can be mixed during the day, fermented, and then placed in the refrigerator for an overnight cold proof as well.