Add flour, yeast, 1 tbsp olive oil and 1 tsp salt into a large bowl. Add 250ml saffron water and mix with a wooden spoon to make a sticky dough. Cover with cling film and put in the fridge overnight or up to 24 hrs.
Once the dough has doubled in size, remove from the fridge and leave in a warm place for no less than 1 hr to bring up to room temperature.
Oil a 23cm (ideally square) roasting tin and scrape the dough in. Oil your hands and push the dough out towards the edge of a tin to create a rough square shape. Cover and leave for about an hour or two in a warm place.
After this further proving time, the dough will be very soft and airy and filled the tin comfortably. Scatter and push in the tomatoes, sprinkle the remaining salt over and drizzle with a little olive oil. Use your fingertips to create dimples in the dough, pressing in the tomatoes and spreading the dough to the corners. Cover and leave to rise for another 1 hr.
Heat oven to 220C/200C fan/gas 7 at least 15 mins before cooking the bread. Uncover the dough, drizzle with the remaining oil and bake on the middle shelf for 20 mins or until golden brown. Cool in the tin for about 10 mins before transferring to a wire rack, or eat warm.