In a large jar with a lid, start by adding the wheat flour.
Pour in the warm water, add the dry yeast powder, the sugar and mix everything together very well until combined.
Cover the jar and let the mixture ferment for 20 minutes.
After this time has passed, add another 200 ml of warm water, a pinch of salt, another 300 g of wheat flour and mix everything very well until combined.
Cover the jar again and let the mixture rise for 1 hour.
After this time has passed, grease the table with some vegetable oil and place the dough that was in the jar onto it.
Sprinkle +100 g of wheat flour over everything and knead the dough a few times.
When the dough becomes smooth and even, roll it out with a rolling pin.
It should be about one-finger thick.
Now, using the grill rack from the oven, score the dough, making diagonal and reverse diagonal lines on it.
Then transfer this dough to a large baking tray, cover it with a dish towel and let it rise for 20 minutes.
After this time has passed, brush a beaten egg over everything.
Add sesame seeds to taste.
Take it to a preheated oven at 180° C (350° F) and bake for 40 minutes.
Serve.