In a large bowl, combine the sourdough starter and water, then add the flour and salt. Stir until it's too stiff to work with a spoon, then use your hand to bring the ingredients together into a uniform dough, about 15 seconds.
Oil the bowl and return the dough, covering the bowl. Rise at room temperature until at least doubled in bulk, which will likely take at least 12 hours.
Once the dough has doubled, you have an additional window of 12ish hours that the dough can remain at room temperature before it needs to be shaped.
Shape the dough and place it into a greased baking vessel, cover and rise on the countertop for 90 minutes.
Score the loaf, place into a cold oven and turn the oven on to 425F / 220C. Bake, covered, for 45 minutes, then remove the cover and bake an additional 15 minutes.
Remove from baking vessel and cool fully before slicing.