In a large bowl, add the water with the yeast to the flour;
Use your hands to mix until the water is absorbed. The dough will be very sticky and very soft;
Cover the bowl with cellophane or a lid and let stand for 10-15 minutes at room temperature;
Dissolve the salt in a tablespoon of lukewarm water; then add it to the dough;
Cover the bowl with plastic wrap once again and let stand for 10-15 minutes;
Add the oil little by little and let it penetrate the dough while working the dough with your hands. When the oil is absorbed, cover it with plastic wrap and let stand for 10-15 minutes;
Now it's time to oxygenate the dough by making folds: take a flap of the dough, lift it and roll it back to the other side. Turn the bowl 90 degrees and repeat this process another three times. Moisten your fingers to work the dough.
Let the dough rest for 30 minutes covered in plastic wrap. After, repeat folding the dough four more times, but let the dough rest for another half an hour;
Take a pan and oil it generously;
Place the dough in the pan and stretch it slightly. Let it rest for another hour, covered in plastic wrap;
To prepare the brine, combine 2 tbsp of water with 2 tbsp of oil in a bowl. Add a pinch of salt, fresh rosemary cut into small pieces, and ground pepper. Blend them well (use an emulsion blender if you have one);
Spread out the dough with your hands. If the dough shrinks back, let it rest a little more. Pour the brine on the dough and use your fingers to massage it into the dough;
Here's the moment: you should feel the bubbles under your fingers;
Garnish it with salt flakes and fresh rosemary;
Bake the focaccia in a preheated oven at 350°F (180°C) for 20-25 minutes;
Check the browning process; your focaccia should be crispy outside and deliciously fluffy like a cloud inside. Let it cool on a rack.