Mix all the flour, potato puree salt, yeast, sugar and 1/3rd of the olive oil in a bowl or by hand. Knead the dough until soft.
Put the dough on to a floured worktop. Cut the dough into three equally large pieces. Make a ball of this and put them in three different deep plates, cover with olive oil. Brush the dough with olive oil and cover it with plastic wrap. Set the plates aside at room temperature to make it rise. It should be about three times the size.
Put two tblsp of the olive oil in a pan about 30 cm in diameter. Put one of the dough balls in the pan. Push with your fingers and gently pull it in the shape of the pan but don't let it tear.
Divide the cherry tomatoes, that have been halved, with the cutting edge down on the dough plus about 10 olives. Cover the pan with a cloth and set aside for another 20 minutes to rise.
Preheat the oven to 220 °C.
Put the pan on the heat and heat moderately. Bake the focaccia as the oil heats up for another 3 minutes. The bottom should turn deep gold brown.
If the oven is raised at temperature in the dough, the pan is in the oven. Sprinkle a tblsp salt and oregano over the dough. Sprinkle approximately one Tblsp of the oregano and some salt over the dough. Sprinkle a Tblsp olive oil over the dough.
Then put the pan in the oven and bake the focaccia for about 17 minutes until it has a deep brown crust. Let it cool down for a few minutes out of the pan. You can eat it hot or cold.
