Combine 1 ½ cups of cool water in a large mixing bowl. Sprinkle 2 teaspoons of active dry yeast over the water and let it sit for about 5 minutes until bubbly. Add 1 cup of pumpkin puree and mix until smooth. Gradually incorporate 4 cups of bread flour and 1 ½ teaspoons of fine sea salt, stirring until a sticky dough forms.

Cover the bowl tightly with plastic wrap and let the dough rise at room temperature for 1 hour, or until it has roughly doubled in size.

After the first rise, wet your fingers to prevent sticking and gently perform several folds in the dough. Cover the bowl again and let it rise for an additional 3-4 hours.

Once the dough has risen, cover the bowl with plastic wrap and refrigerate it for about 12 hours or overnight.

After chilling, turn the dough out onto a floured surface and shape it into a tight round ball. Place it seam-side down on a floured surface and cover loosely with a kitchen towel. Let it rise at room temperature for an additional 3-4 hours.

Preheat the oven to 450°F (230°C) with the Dutch oven (with its lid) inside for 30-40 minutes.

Carefully remove the hot Dutch oven from the oven and score the top of the shaped dough. Transfer the dough into the hot Dutch oven, cover with the lid, and bake for 20 minutes.

After 20 minutes, remove the lid and continue baking for an additional 20-25 minutes, or until the bread is golden brown and sounds hollow when tapped.

Transfer the bread to a wire rack and allow it to cool for at least 1 hour before slicing.