500g '00' flour
2 level teaspoons salt
1/2 packet dried yeast
10oz warm water
3 tablespoons extra virgin olive oil
white flour, for dusting
coarse sea salt, for top
1 large sprig of rosemary
Mix the flour and the salt together in a large mixing bowl. Blend the yeast into the water with your fingers until no lumps remain. Add the yeasted liquid and 2 1/2 tablespoon of the oil to the flour and mix well using a plastic dough scraper or your hand. When the liquid is incorporated, bring all the ingredients together into a ball of dough with your hand. Use the dough to pick up the bits from the sides of the bowl so that you leave the bowl clean.
Turn out the dough onto a lightly floured surface and knead it by pulling, stretching and folding for around 10 minutes. The dough should be soft, but if really sticky add a little more flour. When the dough is worked enough it should bounce back to the touch and feel elastic; if not, keep kneading.
Fold the edges of the dough underneath so that you have a smooth rounded ball. The top side will be the surface of the focaccia. Grease the bowl with some of the remaining oil to prevent the dough from sticking to it. Put the smooth, top side of the dough head-first into the oiled bowl and turn to coat the top and sides with oil. (This will prevent a crust from forming and stop it sticking.) Cover with clingfilm or place a tea-towel over the bowl and leave it in a warm, draught-free spot for about an hour, or until it has doubled in volume.
Preheat the oven to 425°F. Next slide the dough onto an oiled baking tray or roasting tin. Gently ease it out from underneath, trying to keep a good rounded edge. Then use your fingertips to 'make indentations in the dough, flattening it into an oval about 3cm thick. Add your choice of toppings and drizzle over a litle oil, but no salt yet. Break sprigs of rosemary or thyme off the main stem and tuck into the dough; press olives and onion rings into the dough to stop them burning.
Return the dough to rise in its warm place until it is about half as high again, 30-40 minutes. When it has risen, use your fingertips gently to press more indentations into the dough, drizzle with the remaining oil and sprinkle with the rock salt. Bake for 15-20 minutes, until golden brown. If the bottom is not cooked, turn the focaccia over and bake for a further 5 minutes. Allow to cool in a basket or on a wire rack so that it cannot sweat underneath.