1. Combine the biga, water, yeast and slat in a bowl and mix to dissolve the biga by squeezing it through the fingers of one hand. Add the olive oil, then add the flour a cupful at the time, beating all the while. Mix to a dough that has some resilience, then turn it to a floured work surface to knead. It will be quite moist, but will come together with working as the flour takes up all the liquid. Knead for 10 minutes. Leave the dough to rise in a bowl covered with oiled clingfilm in a warm place (24 °C/75F) for about two hours, until nearly doubled in size.

2. Turn out the dough on the lightly floured work surface, knock back and shape into a ball. Prove it either upside down in a floured, cloth lined proving basket or the right way up directly on an oiled and warmed baking sheet. Leave the dough to prove, covered by an oiled clingfilm, for about 1-1.5 hours, until doubled. Meanwhile heat the oven to at least 230 °C/450F/gas 8 and put a deep, but empty, baking tray or roasting pan in the bottom.

3. Dust the loaf lightly and score with a chequerboard of slashes or leave it to crack flreestyle in the oven. Place it in the oven and pour a little water into the wamed baking tray, taking care it does not bubble and scald you in the steam. If you have proved in a basket you will need to have a preheated baking sheet in the oven. Turn your loaf on to a baker's peel then slide it on to the baking sheet.

4. Bake the loaf on an upper shelf in the oven for about 30-40 minutes. If your oven gets really hot, turn it down to 220 °C/425F/gas 7 after 20 minutes to avoid the crust being too browned. The loaf is cooked when is sounds hollow when tapped. Cool on a wire rack.

Per serving: 2255 Calories; 38g Fat (15% calories from fat); 80g Protein; 411g Carbohydrate; 0mg Cholesterol; 4309mg Sodium