How to cook
Heat the oven to 482°F (250 °C), put a bowl of water in it at the bottom. You're going to need a spray bottle with water. Cover a flat oven dish with baking paper and sprinkle with corn flour, corn semolina or wheat bran.
For the fermentation beforehand:
1. Pour boiling water over the flour. Stir so you get a very sticky dough. Let it cool, cover with foil and leave overnight.
Knead a very sticky dough with 1 hand. Take it out of the bowl onto the generously floured counter and knead 10 min., while also putting flour on top. The dough is going to be a sticky one and remain such but when you touch it, it needs to be just a little sticky and able to be cleaned from the counter. Do not add any more flour.
Form it into a ball and leave it in a buttered bowl to rise for 2 hours. After the first hour, knead lightly in the bowl itself to get the air out and leave it to double in volume.
Divide the risen dough into 2 equal parts, about 23 oz (660 g) each. Knead lightly once again and shape them as desired - round is best. Place them in the oven dish and cover with greased foil. Leave them to rise for about 40 min.
Heat the oven to 482°F (250 °C), put a bowl of water in it at the bottom. Before you put the breads in to bake, for a more rustic appearance spray them with a water spray bottle and sprinkle with flour through a sieve. Cut along the sides of the dough with a very sharp knife.
Put the breads in the oven and after 30 sec., sprinkle the sides of the oven with the water spray bottle. Do this 3 more times so there's more moisture. This contributes to better baking. Lower the oven to 428°F (220 °C) and bake about 25-30 min. or until the temperature on its inside reaches 199°F (93°C).
Source: Yoanna Petrova's culinary blog.