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. 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.
Use your fist to knock it back, then knead it again for a further two minutes.
Leave to rest again, but only for 5-10 minutes.
Shape by placing into a shallow baking tray, using your hands to spread it out to a depth of about 1.5cm/¾in, then allow to rise again, covered with a tea towel, until doubled in size - this will take about 30 minutes. Preheat the oven to 200C/400F/Gas 6.
Create a dimpled effect by repeatedly pushing your fingertips gently into the surface of the dough. Drizzle a generous amount of extra virgin olive oil evenly over the dough. Sprinkle over the sea salt and push the small pieces of rosemary into the dough.
Bake for 25-35 minutes or until the top is crusty and cooked through to the base. Serve.