How to make
Mix the sifted flour with the yeast, sugar and salt in a bowl.
Make a well and pour the slightly warmed water and olive oil into it - the stronger the olive oil, the more fragrant the focaccia will be.
Knead a smooth, non-sticky dough and let it rise for 1 hour in a warm place or until it has doubled in size.
Form the risen dough into a ball, flatten it and stretch it out with greased fingers directly on baking paper or a greased baking tray - the rectangular tray that is in every oven is ideal.
You can make the focaccia in a round or rectangular shape.
With the tips of your fingers, make holes all over its surface, but without piercing the dough.
Leave it to rise once more for 20 minutes in a 100°F (40°C) oven.
In the meantime, prepare your onion by cutting it into thin crescents and frying it until soft in the butter and oil.
Spread it over the focaccia evenly and sprinkle with coarse flaky salt.
Bake in an oven heated to 360°F (180°C) until golden for about 25 minutes.
Enjoy your meal!
