In a large bowl, mix the sourdough starter with the water, then add the flour and salt and mix until a consistent but sticky dough forms. You can do this by hand or in your stand mixer.
Cover the bowl with cling wrap and let the dough rise overnight or 8-10 hours.
Turn the risen dough onto the kitchen counter and form it into a ball as best as you can. If the dough is hard to handle, flour your hands but resist the temptation to add more flour. You want a dough with higher hydration or water content for a light, airy loaf. Adding too much flour will make your bread dense. Even if your dough doesn't form into a perfect loaf, it will shape up nicely during baking in the dutch oven.
Prepare a sheet of parchment paper by sprinkling liberally with flour. If you don't have parchment, you can use a kitchen towel sprinkled with flour, but keep in mind that there is a much higher chance of your dough deflating when it rises on a kitchen towel because it will more likely stick to the towel. Place the parchment paper or kitchen towel on a baking sheet.
Transfer the dough onto the parchment paper or kitchen towel, seam side down. Cover (I use the bowl I mixed the dough in), and let it rise another two hours.
About half an hour before your bread is done rising for the second time, preheat the oven to 500 degrees. Place a heavy cast-iron or other oven-safe pot in the oven with the lid on. (I use a 3.2 quart dutch oven that is not enameled on the inside. Enameled is even better.)
Once the dough has risen, carefully remove your heated pot from the oven. Quickly, in a smooth motion, turn the dough into the pot so that the seam side now faces up. A parchment paper makes this much easier because the dough slides off more smoothly. Be very careful doing all this because the pot is very hot. If you find turning the bread into the dutch oven difficult to do without deflating it, you can just transfer the bread into the dutch oven with the parchment paper (don't do this if you used a kitchen towel).
Put the lid back on the pot and bake for 30 minutes. Take off the lid and continue baking the bread for another 20 minutes. The bread will split at the top and char a little, which I love because the charring adds even more flavor.
Once the loaf is baked, remove to a rack and let it cool about half an hour before carefully removing it from the pot. Let the loaf continue cooling on a rack. Slice and serve, or tear it apart with your bare hands (which you just might want to do because who has time for niceties when there's a delicious loaf of bread to be eaten ;) ).