1) Start preparing the focaccia with red onions with the dough. In a bowl, mix the flour with the yeast, join the olive paste and, little by little, 3.5 dl of water lukewarm, stirring quickly with a wooden spoon. Let it sit for 10 minutes, add 1 teaspoon of salt and incorporate it mixing. Then transfer the dough onto the floured work surface and knead it briefly, folding it several times (it must be very soft); transfer it to a bowl greased withoil, cover with cling film and a tea towel and let it rise for 24 hours in the refrigerator.

2) Prepare the filling. Slice the onions and let them dry for 10 minutes in a pan with thevinegar, 4 tablespoonswater and a pinch of salt. Remove the dough from the fridge, sprinkle it in flour, transfer it to a 28 cm diameter pan greased withoil and spread it out with your hands. Let it rest for 10 minutes and cover it with the onions.

3) Put the flat bread in the oven and cook at 200 ° for about 40 minutes. Remove from the oven, spread over the surface olives and the thyme, put it back in the oven for another 10 minutes and serve.