ETA: Having made this one several times now, I'm a big fan of the cold proof- either overnight or during the day for an evening baking. This makes it extra easy to cut a pattern into the top, because the loaf is quite firm. With the overnight ferment, I do in fact preheat the Dutch oven since the loaf is chilled.
A very easy to make sourdough, I accidentally discovered that a little extra rising time does wonders for the size.
There is no need to preheat the Dutch oven either. Following Elaine Boddy's suggestions, I put it in a hot oven covered, for 55 minutes and it turned out fantastic!
