Mix the flour and water until no dry bits remain. Cover and let rest 30 minutes.

Add the starter and salt, then use wet hands to pinch and fold until evenly combined.

Cover and let rise. Perform 3–4 sets of stretch and folds over the first 2 hours, then let the dough rise undisturbed until nearly doubled and jiggly, 4–6 hours total.

Turn the dough onto a floured surface, shape it into a tight round, and place seam-side up in a floured banneton.

Preheat a Dutch oven at 450°F (230°C) for 30 minutes. Turn the loaf onto parchment, score the top, and bake covered for 30 minutes. Uncover and bake 15–20 minutes more until deep golden. Cool on a rack and slice.