Combine the starter, water, flour, and salt in a deep bowl. Stir with a wooden spoon until mixed. It'll be scraggly looking, don't worry.
Dust a counter with flour, and scrape the dough out onto it. Dust a bit more flour on top. Knead until it forms a smooth dough, 8 to 10 minutes, dusting lightly with more flour as needed.
Shape the dough into a round, and add to a floured proofing basket, if you have one. Alternately, you can line a deep bowl with a clean, non-terry dish towel. Generously flour the towel, and place the round of dough in it.
Cover the proofing basket with a piece of plastic film. Let rest in a cool spot overnight, or 6 to 8 hours.
The next morning, add a stone bread baker, or ceramic dutch oven to the center rack of your oven. Preheat the oven to 500ºF (260ºC).
Remove the stone pot from the oven, and gently, but swiftly, turn the dough out of the basket and into the pot. Make slashes, as desired with a sharp paring knife or razor. Cover and bake 30 minutes. Remove cover, and let bread bake 10 to 15 minutes more until the crust reaches your desired level of doneness. Best to start checking at 10 minutes if you prefer them less well-done.