In a large bowl whisk together 250 grams warm water, pumpkin puree and sourdough starter. Add flour and sea salt and mix until the flour has been fully incorporated. Cover and let rise at room temperature for 45 minutes to an hour.
While the dough rises add dried cranberries, dark brown sugar, vanilla extract, pumpkin pie spice and remaining 1 tablespoon of water to a small bowl and mix.
After the dough has rested add the cranberry mixture in three equal intervals kneading between each addition. This ensures that the cranberries are more equally distributed within the dough. Once the cranberries have been fully incorporated cover the dough and let it rise, at room temperature, for an additional 6 to 8 hours.
Once the dough has doubled in size prepare a batard shaped proofing basket by either lightly flouring it or lining it with a tea bowl. Pour the pumpkin seeds out onto a flat surface and pat into a thin, even layer.
Turn the dough out onto a lightly floured surface and shape into a batard (oval). To shape the dough fold the right side over to the middle of the dough, leaving roughly 1/3 of the dough uncovered. Repeat with the left side of the dough. To understand this process think of folding a letter. Using both hands grab the top of the dough and stretch gently up and away before rolling it towards you. Continue to roll the dough into a tube being sure to create as much tense as possibly by tucking the dough in tightly as you roll. Let the dough rest on it's seam. Pinch both ends of the batard to close the open seams.
Brush the dough with a damp pastry brush to create a thin layer of water. Using a bench scrapper gently pick up the dough and place it, wet side down, on the pumpkin seeds. Rock the dough back and forth and side to side to get it evenly covered. Using a bench scrapper once again gently pick up the dough and place it seam side up in the prepared proofing basket. Cover and refrigerate for 10 to 12 hours before baking.
Preheat oven and dutch oven to 450F. Turn dough onto a sheet of parchment paper and score, top to bottom, using a bread lame or serrated knife. Bake with the lid on for approximately 50 minutes. Remove the lid and bake for another 10 minutes or until the internal temperature has reached 205F.
Remove the loaf from the dutch oven and allow to cool on a wire rack for one hour before slicing.