1. Cook the pasta according to pack instructions. Meanwhile, heat the oil in a large frying pan, then fry the onion over a medium heat for 5 mins until soft. Add the garlic and cook for another min.
2. Rinse the capers and add to the pan with the tomatoes, peppers and olives. Check for seasoning, then cook for a few mins more until heated through. Drain the pasta and toss with the sauce. Serve with lots of grated cheese, if you like.