Mix flour and salt in a large bowl, add water and starter, and mix until no dry flour remains. Cover and rest 30 minutes. Perform three sets of stretch and folds, 30 minutes apart.

Cover tightly and let rise at room temperature for 10 to 12 hours, until tripled and jiggly.

Turn out onto floured surface, fold into a round, and shape into a tight ball with surface tension.

Place seam-side up in a floured banneton, cover, and proof 1 to 2 hours until puffy and a finger poke slowly springs back. Preheat Dutch oven to 450°F (230°C) 30 minutes before the proof ends.

Invert dough onto parchment, score the top, lower into the hot pot, and bake covered for 25 minutes. Uncover and bake 15 minutes more until deep brown.

Cool on a rack at least 1 hour before slicing and serving.