Preheat the oven to 220°C/fan 200°C/gas mark 7. Place the peppers and tomatoes in a large baking tray, then drizzle with ½ tbsp olive oil and season. Bake for 15 minutes, until cooked and lightly charred. Remove from the oven and set aside.
Add the flour to a large mixing bowl with the baking powder and dried herbs. Season lightly and whisk together. Make a well in the centre and add 2 tbsp olive oil. Gradually add 125ml warm water, using a fork to bring the fork into the liquid.
Once it has roughly come together, turn the dough out on to a lightly floured work surface and knead for 8-10 minutes until you have a smooth ball of dough. Turn a large bowl over the dough and leave to rest for 30 minutes.
Add the remaining oil to a medium-sized ovenproof frying pan, making sure it coats the bottom. Place over a medium high heat, then stretch the dough to the size of the pan and carefully add to the pan. Cook on one side for 4-5 minutes until deeply golden, then turn over. Continue to cook for another 5 minutes, lowering the heat if it starts to burn.
Mix half the roasted cherry tomatoes into the tomato purée. Spread the tomato mixture on to the pizza and top with the remaining roasted veg and mozzarella pearls. Place under a hot grill for 3-4 minutes, or until the mozzarella just begins to melt. Remove from the oven and scatter with the basil leaves. Serve with the salad.