Autolysis: sift the flour, add the water. Leave to rest for 1 hour.
Add the active sourdough starter, 1 tablespoon of fat, the grated boiled potatoes and start kneading the dough. Then add the salt at the end and knead the dough completely. Put the dough in a greased rising bowl and let it rest for 1 hour.
Start folding the dough in any way you like and let it rest for 30 minutes.
Fold the dough a second time and let it rest for 30 minutes.
Fold the dough a third time and let it rest for 1 hour.
Divide the dough in half and pre-shape them, then let them rest for 10 minutes.
We do the final shaping, pinching and rolling the dough, then we put it in a sliding door, cover it with a kitchen towel and refrigerate it for about 12 hours.
Take the dough out of the fridge and let it temper on the counter.
Preheat the oven to 250°C on the bottom-up baking programme.
Turn the dough out onto baking paper and shape as desired.
Once heated, place in the oven to bake. Baking on a pizza stone: 250 degrees for 20 minutes, then reduce the temperature to 200 degrees for 15 minutes and finally reduce to 180 degrees for 25 minutes. Bake for about 1 hour in total.