In a large bowl combine the starter, water, sugar and vanilla. Stir with a fork. Sift the bread flour and cocoa powder together and add to the bowl. Squish everything together with your hands until all of the flour is absorbed. Cover with plastic wrap and let it rest (autolyse) for 1 hour.

Add the salt, walnuts, raisins and chocolate chips. Lift and fold the dough over itself several times and squish with your hands to incorporate. The dough will tear slightly as you fold. Don’t worry- this is normal. Work the dough as best you can until it comes back together into a rough ball.

Cover the bowl with plastic wrap and a clean kitchen towel. Leave it in a warm spot to rise. Your dough is ready when it no longer looks dense and has increased in volume about 1½- 2x its original size. This can take anywhere from 10 hrs @ 68 F; 5-6 hrs @ 75 F; 3-4 hrs @ 80 F depending on the temperature of your ingredients, the potency of your starter and surrounding environment.

To cut and shape the dough, divide your work surface in half; lightly flour one side (for cutting) and leave the other half clean (for shaping). Remove the dough from the bowl and place onto the floured section. You do not need to ‘punch down’ the dough; it will gently deflate as you fold and shape it. Cut the dough in half to make 2 loaves, or leave it whole for a single loaf.

Place the dough into a cloth lined 8-inch bowl or floured/lined proofing basket. It will need to rise again, about 30 minutes to 1 hour. It is ready when the dough is slightly puffy, but not double in size.

Towards the end of the second rise preheat your oven to 400 F. Cut a sheet of non-stick parchment paper to fit the size of your baking pot, leaving enough excess around the sides to remove the bread.

Place the parchment over the dough and invert the bowl to release. Using the tip of a bread lame, small, serrated knife or a razor blade, make four shallow 4-inch long cuts at 3, 6, 9, and 12 o’clock around the dough. Use the parchment paper to transfer the dough to the baking pot.

Place your bread into the oven (lid on) and bake for 20 minutes. Remove the lid, and continue to bake (uncovered) for an additional 40 minutes. During the last 10 minutes of baking, crack open the oven door. This allows the moisture to escape, leaving your bread with a crisp crust.

Remove the bread from the oven, and cool on a wire rack for at least an hour before slicing. Dust with powdered sugar before serving.