Add water, sourdough starter, and flour to a large mixing bowl. Mix well until the flour is hydrated and there are no more dry spots. Cover with a damp tea towel and let rest for 30 minutes.
Add the salt, knead thoroughly, and cover again with a damp tea towel for another 30 minutes.
Perform a set of stretch and folds. Using your hands, take one of the edges of the dough, pull it upward, and press it back into the center. Turn the bowl a quarter turn and repeat this four times total. Cover and let the dough rest for 30 minutes.
Repeat step 3 two more times waiting 30 minutes between, stretching and folding the dough. Cover and bulk ferment for 8-12 hours or until doubled.
Transfer the dough to a lightly floured surface. Pat it out into a circle that is approximately 1 inch thick. Chop the block of cream cheese into cubes and place them evenly over the top of the dough.
Sprinkle sugar over the cream cheese, then scatter the fresh blueberries evenly over the top. Press them gently into the dough so they don't roll around.
Fold two sides of the dough in, followed by the other two sides. Roll it up, folding the edges in. Create tension in the boule by rolling it across the countertop. If blueberries and cream cheese pop out, do your best to pop them back in and pinch the dough closed.
Place the bread dough in a floured banneton or a bowl lined with a tea towel. Refrigerate for 12-15 hours.
Place your Dutch oven into the oven, and preheat to 450 for one hour.
Gently turn out the fermented ball of dough onto a piece of parchment paper, score, and place it into the preheated Dutch oven.
Place covered dutch oven back into the oven and bake for 30 minutes. Remove cover and bake for 20-25 minutes or until golden brown. The internal temperature should be 190 degrees. Cool completely on a wire rack before slicing.
Notes
Feed your starter 4-12 hours before starting the recipe. Begin the recipe when your starter is most active.
Be gentle when handling the blueberries so they aren't smashed.
Pulling the dough across the counter to create tension will help the boule to rise upward more than outward. This helps the dough rise more effectively, resulting in better oven spring.
If you don’t have a Dutch oven, you can place the bread on a baking sheet, set a pan of water on the rack below it, and spritz the loaf with water several times during baking to help create a nice crust.