In a large mixing bowl, combine all-purpose flour, lukewarm water, and your active sourdough starter. Mix until fully incorporated and cover with a towel for 30 minutes.

Sprinkle salt over the dough and knead thoroughly for about 5-10 minutes until well-developed and elastic. Rest again for another 30 minutes.

Perform a series of stretch and folds every 30 minutes over the next 2 hours, and let it bulk ferment for 8-12 hours.

Dust a clean surface with flour, turn the dough out, and flatten it. Distribute cream cheese cubes and blueberries, then fold and shape into a boule.

Transfer the boule into a floured banneton. Cover and refrigerate for 12-15 hours for cold proofing.

Preheat your Dutch oven to 450°F for an hour. Score the top of the boule and bake covered for 30 minutes, then uncovered for 20-25 minutes.

Let the bread cool on a wire rack for at least an hour before slicing.