Stir starter and water together until dissolved. Mix in flour and salt to form a shaggy dough. Cover and rest 30 minutes.

Scatter cheese over the dough, then fold and tuck until cheese is evenly incorporated, about 8 to 10 folds. Cover and rest 30 minutes, then do another 4 folds.

Over 2 hours, do 3 to 4 sets of stretch and folds, spacing them 30 minutes apart, until the dough is smooth, elastic, and puffy.

Shape the dough into a taut round on a floured surface, place seam side up in a floured banneton or bowl, and let proof until puffy and a poke springs back slowly.

Preheat a Dutch oven at 450°F (230°C) for 30 minutes. Turn dough onto parchment, score deeply, transfer to the hot pot, cover, and bake 35 minutes. Uncover and bake 10-15 minutes more until deep bronze.

Cool completely on a rack, at least 1 hour, then slice thick with a serrated knife and serve.