In a big bowl, mix all the ingredients for day 1 with a spoon until the mixture looks like porridge. Cover the bowl with cling film and leave at room temperature for 12 hrs, until it doubles in volume. I do the mixing in the evening around 8 p.m. so the next morning I can proceed with the next steps.
Once the 12 hours have passed, add to the bowl all the ingredients for day two and mix everything for a good 5 minutes. Forget about the normal consistency of bread dough, this will look like a muddy mess, and that's ok.
Lightly oil a 500 g loaf tin, transfer the dough in it by spoonfuls and smooth the surface. Sprinkle a little flour or oatmeal (I love the way the bread looks with a bit of oatmeal to coat it!) on to the top of the loaf.
Leave to rise again, but this time uncovered, until nearly doubled in size: it will take more or less 5 hours at room temperature, of if you prefer slow rising, 8 hours in the fridge: the time will depend on the strength of your starter and the temperature, so try and see how it works for you.
Preheat your oven to 450ºF.
Place the loaf in the oven and bake for about 40 minutes; when you are roughly halfway through, open the oven to turn the loaf around and let the steam escape, which will benefit the crust.
Once the bread is perfectly cooked, let it come back to room temperature and - if you can resist - allow it to sit for 12 hours, wrapped in parchment paper, before you slice it.