1. Sieve the flour into a bowl, press out an indent and pour the warm water and 2 tablespoons of olive oil into this hollow. Sprinkle the yeast on top and add the half teaspoon of salt. Knead everything together to form a smooth dough. Cover with a cloth and leave to prove in a warm place until the volume has doubled - around 30 minutes.
2. Pre-heat the oven to 200°C lower-upper heat. Knead the dough and roll out to approximately the size of the baking tray. Cover the tray with a sheet of baking paper and brush 2 tablespoons of olive oil over the surface. Place the dough on top and press out some holes using your fingertips. Remove the rosemary from the stem and spread over the top, sprinkle some salt and drizzle the remaining olive oil on top.
3. Leave to prove from another 20 minutes before baking, then place in the oven and bake for 15 to 20 minutes until golden brown.