toppings of your choice, such as olives, sliced red onion, artichoke or ham (optional)
rocket leaves, to serve (optional)
400g tin plum tomatoes
1 tsp baking powder
4 sprays olive oil spray
½ tsp salt
300²µ/10½´Ç³ú self-raising flour, plus extra for dusting
200g/7oz firm mozzarella cheese, grated
300²µ/10½´Ç³ú plain yoghurt