Autolyse: Mix flour and water in a large bowl. Rest covered for 30 mins.
Add Starter and Salt: Mix in starter, then salt until well incorporated.
Bulk Ferment: Cover and rest at room temp. Perform 4 sets of stretch and folds 30 mins apart.
Pre-shape and Rest: Turn out dough, shape into a ball, rest 20 mins.
Shape: Shape into a tight ball or oval. Place in floured banneton or towel-lined bowl, seam-side up.
Cold Ferment: Cover, refrigerate overnight (12+ hours).
Bake: Preheat oven to 500°F with Dutch oven inside. Score dough, place on parchment, into Dutch oven. Bake at 450°F covered for 20 mins, uncover, reduce to 425°F, bake 15-20 mins until golden.
Cool: Cool on wire rack for 1 hour before slicing. Enjoy your loaf!