Start by placing the flour into a large bowl. On one side of the bowl add the yeast and on the other side add the Maldon salt, then mix everything together with a wooden spoon until combined. Create a well in the middle of the flour and pour in the lukewarm water and 2 tbsp of olive oil, and then mix until you have a sticky dough. You can either knead this on a lightly floured surface for 10 minutes, or you can do this in an electric mixer with the dough hook attachment – knead until the dough is smooth and slightly less sticky. Once kneaded place the dough in a lightly oiled bowl and cover with a clean tea towel. Leave in a warm place and allow the dough to prove for 1 hour until it has doubled in size.
Preheat the oven to 200C. After the dough has proved, knock the air out by kneading it again briefly and deflating it. Grease a 25 x 35 cm baking tin with olive oil. Pull and stretch the dough so it roughly fills the bottom of the tin, then place the tea towel back over it and leave it to prove once again for 30 minutes.
After 30 minutes your dough is ready to bake. Use your fingers to make dimples in the top of the dough and to help spread it into the corners of the tin. Dot the cherry tomato halves across the top and then add small sprigs of the rosemary in and around them. Drizzle over 2 tbsp olive oil and sprinkle with Maldon salt. Place into the hot oven and bake for 25 – 30 minutes until golden brown on top and the tomatoes have softened and charred slightly.
Remove from the oven and drizzle over the remaining 1 tbsp olive oil to soak into the warm bread. Allow to cool slightly before removing from the tin and slicing up whilst still warm. Serve with a mixture of olive oil and balsamic vinegar to dip the bread into.