Put the flour, water and oil in a pot. Dissolve the yeast in half a glass of hot water and pour into the pot with the flour.
Start mixing, using a spoon. Add the sugar. Clean a work surface and sprinkle it with flour. Turn the dough over, which will initially be sticky. With the help of flour, mix the dough by hand for 2 minutes and then add the salt (half a teaspoon). Rinse the used pot at the beginning, dry it and put the dough in it, covered with a clean cloth. Let it rest for 15/20 minutes. Once the time has passed, put it back on the shelf and work it again for another 2/3 minutes. Put it back in the pot, covering it with transparent film on which holes will be made with the help of a fork. Cover with the tea towel and leave for 1 hour.
After 1 hour the dough will have doubled its volume. Cover a baking dish with baking paper. Pour in extra virgin olive oil and place the focaccia. With the help of the hands spread the dough over the pan, pressing lightly with your fingertips. Dissolve 4 tablespoons of hot water and 1 tablespoon of salt in a glass. Pour the liquid on the focaccia evenly. Oil the surface and bake at 180 ° C in a preheated oven for 30 minutes. Check the cooking with the help of a toothpick, re-oil the surface and prolong cooking for another 10 minutes.
The focaccia is good if served warm (or heated), sprinkled with black pepper and aromatic herbs.