Cut tomatoes into quarters or halves, finely chop half rosemary, peppers and onions cut into chunks, four cloves of garlic (leave skin on). Put all in a baking tray, toss them and sprinkle some salt, the olive oil and freshly grind some black pepper. Place in the oven and roast for 25-30 min. At this point you can increase the oven temperature to 200 C/ 400 F/ Gas mark 6 if you wish. Don’t forget to sprinkle the balsamic vinegar if you choose to put it in. It’s really nice I do recommend you try it.