Preferment:

Pour the water into a bowl and dissolve the yeast in it. Add the flour and lightly mix it into a dough. Cover the bowl with plastic wrap and let the preferment rise at room temperature for 10-12 hours.

Dough:

Pour water into the bowl and add the preferment and the two types of flour. Mix briefly and let it rest for 30-40 minutes (autolyse). Add salt. Knead the dough in a stand mixer for 3 minutes at low speed and 5-8 minutes at medium-high speed until the dough pulls away from the bottom of the bowl. Wet your hands, lift the dough and fold it under itself. Place the dough in an oiled bowl and cover with plastic wrap. Let the dough rise until almost doubled in size (2-4 hours depending on room temperature). Preheat the oven to maximum temperature (preferably 270 degrees Celsius (518 degrees Fahrenheit)). Generously flour the table and pour the dough onto it. Fold the four sides of the dough towards the center to form a square and generously flour it. Cut the dough into 9 or 12 pieces and place them on a piece of parchment paper. Place a baking tray with boiling water at the top of the oven. Bake the rolls at the bottom of the oven for 15-20 minutes