In a large mixing bowl, combine the flour, water, salt, and sourdough starter. Stir until a shaggy dough forms. Cover with a damp towel and let rest for 30 minutes.
After resting, begin stretch and folds. Grab one edge of the dough, stretch it upward, and fold it over itself. Rotate the bowl and repeat 3 more times. Do this every 30 minutes for a total of 4 sets over 2 hours.
Shape the dough into a round ball and place it in a lightly floured bowl or banneton, seam-side up. Cover and refrigerate overnight (8 to 12 hours).
The next day, place your Dutch oven in the oven and preheat to 450°F. Let it heat for at least 30 minutes.
Carefully turn the cold dough out onto a piece of parchment paper. Score the top with a sharp knife or bread lame.
Use the parchment paper to transfer the dough into the hot Dutch oven. Cover with the lid and bake for 30 minutes.
Remove the lid and bake uncovered for another 15 to 20 minutes, until the crust is deep golden brown.
Lift the bread out and let it cool completely on a wire rack before slicing. (Yes, the wait is tough, but it is worth!)