1. Combine starter and water in a bowl and stir to disperse the starter.

2. Add both flours and mix until no dry spots remain, then cover and autolyse for 30–45 minutes.

3. Sprinkle salt over the dough, pour in orange juice, and knead until incorporated.

4. Gently fold in orange zest and cranberries until evenly distributed.

5. Perform 3–4 sets of stretch and folds every 30–45 minutes during a 2–3 hour bulk fermentation.

6. Cover the dough and let it rise until 50–75% larger, about 4–6 hours at room temperature.

7. Shape the dough into a round or oval and place seam-side up in a floured banneton.

8. Cover and refrigerate overnight (8–12 hours) for cold fermentation.

9. Preheat oven to 450°F with a Dutch oven inside for 30 minutes.

10. Turn dough out onto parchment, score the surface, and transfer to the hot Dutch oven.

11. Bake covered for 20 minutes, then uncover and bake 20–25 minutes until deep golden.

12. Cool on a wire rack for at least one hour before slicing.