In a jar, combine 1/2 cup bread flour, 1/2 cup whole wheat flour, and 1 cup water; cover loosely and let sit at room temperature for 8 to 12 hours until bubbly. In a large bowl, whisk together 3 3/4 cups (450g) bread flour and 1 3/4 teaspoons (10g) fine sea salt. Add 1 cup (240ml) water, 1/2 cup (120g) of the bubbly fed starter, 3/4 cup (180g) pumpkin puree, and 2 tablespoons (42g) honey. Mix with a spatula until a shaggy dough forms, cover, and rest for 30 minutes. Perform 3 sets of stretch and folds at 30 minute intervals. Let the dough bulk ferment at room temperature (around 75°F) for 3 to 4 hours, or until it has grown by about 40% and feels airy.

Turn the fermented dough out onto a lightly floured surface. Gently pre-shape it into a round by folding the edges into the center. Using a bench scraper, rotate the dough in a clockwise (or counterclockwise if you are left handed) motion until the top becomes smooth and taut. Let it rest for 10 to 15 minutes, then tighten the round once more just before proofing.

Place the shaped dough seam-side up in a banneton basket or a large bowl lined with a tea towel. Cover with a tea towel or a plastic bag and refrigerate for 12 to 15 hours to cold proof.

Preheat your oven to 420°F and place a Dutch oven with its lid inside to preheat as well.

Cut a large piece of parchment paper, dust it with flour, and lay out 8 pieces of kitchen twine in a spoke pattern radiating from the center, like a pizza cut into 8 slices.

Place the cold dough seam-side down in the center of the twine. Bring the ends of each twine piece up and over the dough, then tie them firmly into knots, working around the dough to create 8 pumpkin sections.

Set the twine-wrapped dough on top of the preheating oven or another warm spot to help it come to room temperature more quickly.

Once the oven is fully preheated, use a lame or sharp knife to score along each twine line, just to one side of the twine so the pumpkin shape holds during baking.

Transfer the dough on the parchment into the hot Dutch oven, cover, and bake at 420°F for 25 minutes. Remove the lid and bake for another 25 minutes until deep golden brown.

Cool the loaf completely on a wire rack, then carefully remove the twine and push a cinnamon stick into the top to form the stem.