Place the chocolate chips in the freezer.
Start with the autolyse.
Mix the flour and water.
Knead for 4 minutes.
Let rest for 30 minutes.
Add the sourdough starter when it is nice and bubbly, the maple syrup, and the yeast (optional).
Knead for 15 minutes on first speed.
Add the salt.
Knead for 5 minutes, adding water if necessary (if the dough is too stiff). Knead until the gluten network forms.
Mix the cocoa with 90 ml of water to create a paste.
Add the cocoa mixture to the dough and knead to incorporate.
Add the chocolate chips and gently knead until the mixture is uniform.
Place the dough in a bowl and let it ferment for 4 hours at room temperature (or overnight in the refrigerator).
Preheat the oven with a baking stone to 260°C (500°F).
Generously flour a cotton towel. Place the dough on the towel. Fold the dough into a square using the towel.
Cut into squares.
Place in the oven (if you want to keep the baking stone clean, we recommend using parchment paper).
Bake for 15 minutes or according to the size of the pieces.