[nana77]

Thought that I'd get a quite-proper result.
Notes: had to know that on that recipe, that has two leavenings, the first one has to exact double (no less, no more, so choosing a vertical container helps, instead of bowls); the second other just needs few hours (the rest of the levering gets done on the oven: previously I was waiting too much and the sourdought always loose its forces).
Adding durum wheat semolina outwardly gives a nice and tasty crust, too.