Preparation

• Prepare the Levain: In a mixing bowl, combine 30 g of your sourdough starter with 60 g of all-purpose flour and 60 g of water. Stir well until the mixture is fully incorporated. Cover and let rise for 4 to 6 hours.
• Mix the Dough: In a separate bowl, combine 45 g of cocoa powder with 100 g of just boiled water. Stir until smooth, then add 250 g of cold water, 50 g of sugar, 8 g of salt, 1 tsp of vanilla extract, and 460 g of all-purpose flour. Mix until just combined.
• Incorporate the Levain: Add the prepared levain to the chocolate mixture and mix with a fork, then use your hands until the dough comes together.
• Autolyse: Let your dough rest for 10 minutes.
• Stretch and Fold Technique: Stretch and fold the dough every 20 minutes for 2 hours.
• Bulk Fermentation: Allow the dough to rise undisturbed for about 4 hours until nearly doubled.
• Shape the Dough: Turn the dough onto a floured surface, shape it into a rectangle, sprinkle dark chocolate chips, fold over and seal.
• Final Shape: Shape into a ball and place seam-side up in a floured banneton basket, cover with a towel.
• Cold Fermentation: Refrigerate for at least 8 hours, up to 24 hours.
• Preheat the Oven: Preheat the oven to 450°F (230°C), place a Dutch oven inside to heat up.
• Bake: Turn the dough onto parchment, score the top, lift and place it in the hot Dutch oven. Cover and bake for about 30 minutes.
• Crust Development: Remove the lid and bake for an additional 15-20 minutes until golden brown.
• Cool: Transfer to a wire rack to cool completely before slicing.