Pour a little of the tepid water into a small bowl. Add the yeast and blend using your fingers. Leave the yeast for five minutes to soften and dissolve.
Mix the flour and salt together in a large mixing bowl. You may like to transfer your mixture to a pastry board or other flat work surface at this stage and prepare the dough there, in traditional Tuscan style. Otherwise, mix the dough in the bowl.
Make a well in the centre of the flour and salt mixture. Pour the blended yeast and water into the well along with the olive oil. Mix thoroughly. Gradually add the rest of the tepid water until a sticky dough is formed.
Transfer the dough onto a floured surface if you haven't already. Gather any stray pieces. Knead the dough for about 10 minutes, adding a little extra flour if necessary, until smooth and elastic and the dough no longer sticks to your hand. To see if it is ready, you can carry out the stretch test: pull off a piece of dough; it should be elastic enough not to break quickly when stretched out.
Next accumulate any stray ends and rough sections by 'chafing' your ball of dough. Hold it and curve your hands around it, use your palms to pull at its sides gently while you slowly rotate it, letting your little fingers meet underneath. Do this for five minutes. You should be left with a neat, smooth ball.
Oil a bowl and place the dough inside and cover with either oiled cling film or a damp tea towel. Leave in a warm place to rise until doubled in size - about 1½ hours depending on the room temperature.
Preheat the oven to 240C/475F/Mark 8.
Use your fist to knock back the dough, then knead it again for a further two minutes. Leave to rest again, but only for 5-10 minutes.
Use a little olive oil to grease a baking sheet. On a floured surface, roll out the dough as thinly as you can to make a square to fit the baking sheet. Put the dough onto the baking sheet and push it out to the edges.
To make the pizza, spread the tomato passata thinly over the dough. Scatter over the mozzarella, oregano, olives, garlic (if using), and, if you like, some chilli. Season with salt and freshly ground black pepper.
Place on the highest shelf of the oven and bake for 10-15 minutes until the base is crisp and the mozzarella is melted. Serve.