Schiacciata, literally meaning squashed, is a crisp Tuscan bread made with flour, yeast, olive oil and water. During the grape season in Florence, cooks often add sugar and a topping of grapes and fresh rosemary to make a sweet-and-savory version called schiacciata all'uva.
Schiacciata was first made during the Middle Ages when it was used to test the oven temperature before baking the bread. Today, it is prepared savory and sweet.
Mix the sourdough with the flour and water, work for at least 10 minutes, until the dough becomes nice and elastic. Let the dough rest for about 10 minutes.
Take the dough again and work very well for another 5-10 minutes.
Finally add the salt and mix, continuing to work the dough for a few minutes.
Extend the dough into a rectangle with oil-greased hands, then make a three-fold (fold in 3), seal all the sides with the fingertips so that the bubbles of air do not come out, cover with a plastic sheet and let stand for 30 minutes. Then make another fold and let rise until doubled in size inside a pan oiled with extra virgin olive oil and cover the top with film. The time to double depends on the temperature of your kitchen - roughly 8 hours or overnight in the fridge after a couple hours on the counter. If you use the yeast instead of sourdough starter, it will take half the time.
Now turn the dough on the oven pan greased well with extra virgin olive oil, gently spread the dough, leaving the edges a little thicker and let it rise until the crush does not make the "bubbles" and it will be doubled again. If you take the dough out of the fridge before doing this, leave it at room temperature for at least 1 hour, better if it is not too hot, and then proceed.
Brush with plenty of olive oil and sprinkle with salt and fresh rosemary.
Bake at 210 °C for about 10 minutes, then lower it to 180 °C for another 15 minutes and open the oven so that the last 10 minutes dry well.
Allow to cool well before cutting!!