In a large mixing bowl, combine 100g of active sourdough starter with 240g of room temperature water, then add 200g of pumpkin puree. Mix until smooth.

Gradually incorporate 500g of bread flour into the mixture until fully combined. Cover the bowl and let it rest for 30 minutes.

Sprinkle 10g of coarse kosher salt over the dough. Use wet hands to perform stretches and folds, resting for 30 minutes between each stretch.

In a separate bowl, whisk together 50g of brown sugar, 1/3 cup of chopped dried cranberries, and 1.5 tbsp of pumpkin pie spice. Sprinkle on dough and fold to combine.

Cover the bowl tightly and allow the dough to bulk ferment for 10-12 hours at room temperature.

Turn the dough onto a floured surface, pre-shape into a loaf, place on parchment, cover with a cloth, and let rise for 60-120 minutes.

Preheat a Dutch oven in a cold oven to 450°F (232°C) about 30 minutes before baking.

Score the dough surface, place it in the hot Dutch oven and bake covered for 30 minutes. Then remove the lid and bake for 15-20 minutes until golden brown.

Transfer the bread to a wire rack and let it cool completely before slicing.