Confirm your starter is ready. Feed it 6–8 hours before mixing. It should be domed, bubbly, and float in water. If it sinks, feed and wait.

In a large bowl, mix bread flour, whole wheat flour, pumpkin puree, and 170 g warm water until no dry spots remain. The dough will be shaggy and slightly stiff. Cover and rest 30–45 minutes.

Mix in the active starter, brown sugar, sea salt, cinnamon, ginger, and nutmeg.

If the dough feels tight, add up to 30 g more water, a little at a time.

Use stretch-and-folds in the bowl for 2–3 minutes or a gentle slap-and-fold on the counter for 2–4 minutes.

Transfer to a clean, lightly oiled bowl. Over the first 2 hours, do 3–4 sets of coil folds every 30 minutes, then let it rest undisturbed.

Watch the rise, not the clock: at 75°F/24°C, bulk takes 4–6 hours. Look for ~60–80% rise.

Turn the dough onto a lightly floured surface. Gently tighten into a round using a bench scraper. Rest for 20 minutes.

Shape into a batard or boule, and proof seam-side up in a floured banneton for 45–75 minutes at room temperature.

Preheat the oven. Heat a Dutch oven inside at 475°F (245°C) for at least 30 minutes.

Turn the dough onto parchment, score it, and load into the Dutch oven.

Bake covered for 20 minutes at 475°F, then uncover and reduce to 450°F (232°C). Bake another 20–25 minutes until deeply bronzed.

Wait at least 1–2 hours before slicing. The crumb finishes setting as it cools.