It had to happen! I was very pleased with these. They are not quite as light as conventional HXBs because sourdough is always chewier, but the crumb is soft and buttery, the crust light and soft. A definite hit, to be repeated. The recipe is from the Clink restaurant; I’m reproducing it here having converted it to metric from annoying cups. I give it in stages as it was in the original, because that’s the most effective way to plan it. The baking process itself will take about 2 1/2 hours including proving.
You don’t need bread flour for this; ordinary white flour is fine. I used organic white flour (T65).
The dough is very sticky. If you have a stand mixer, I recommend using it with the dough hook. Otherwise, sprinkle your work surface with flour, have a dough scraper handy, and be prepared for messy hands.