In a large mixing bowl, combine the bread flour, pumpkin spice, and salt.

Add the active sourdough starter, pumpkin puree, water, and brown sugar or maple syrup. Mix until a shaggy dough forms, adding the optional olive oil or melted butter if using.

Let the dough rest for 30 minutes, then stretch and fold in the dried cranberries until evenly distributed.

Cover the bowl and allow the dough to ferment at room temperature for 4 to 6 hours, performing 3 to 4 sets of stretch and folds during the first 2 hours, until the dough becomes smoother and slightly puffy.

Shape the dough into a round loaf and place it seam-side up in a floured proofing basket or bowl.

Cover and proof for 2 to 4 hours at room temperature, or refrigerate overnight for a deeper flavor.

About 30 minutes before baking, preheat the oven to 450°F (230°C) with a Dutch oven inside.

Carefully transfer the dough to parchment paper, score the top, and place it into the hot Dutch oven.

Bake covered for 20 minutes, then remove the lid and bake for another 20 to 25 minutes, until the crust is deep golden brown and the loaf sounds hollow when tapped.

Cool the bread completely on a wire rack for at least 1 hour before slicing.