1. Feed starter 6–8 hours before mixing until bubbly and doubled.

2. In a bowl whisk flours and cocoa powder together.

3. In a separate bowl combine pumpkin puree, water, starter and sugar.

4. Pour wet mixture into dry and stir until no dry bits remain.

5. Cover and rest for 30 minutes (autolyse).

6. Add salt and oil, then perform 3–4 stretch-and-folds over 2 hours.

7. Gently fold in chocolate chunks until distributed.

8. Shape dough into a boule and place seam-side up in a floured proofing basket.

9. Proof at room temperature until doubled, or refrigerate overnight for flavor.

10. Preheat oven with a Dutch oven to 450°F (230°C).

11. Transfer dough to parchment, score top, and bake covered 20 minutes.

12. Uncover and bake 20–25 minutes until crust is deep brown.

13. Cool on a rack at least 1 hour before slicing.