Heat the oil in a large pan and cook the onion for 8-10 mins until starting to caramelise (or for longer if you have time – the sweeter the better). Add the garlic for the final 2 mins of cooking time.
Tip in the mixed veg, tomatoes, capers and raisins. Season well and simmer, uncovered, for 10 mins, or until you have a rich sauce.
Meanwhile, boil the kettle. Pour the kettleful of water into a large pan with a little salt and bring back to the boil. Add the pasta and cook until tender with a little bite, then drain, reserving some of the pasta water. Tip the pasta into the sauce, adding a splash of pasta water if it needs loosening. Scatter with the basil leaves and parmesan, if you like, and serve straight from the pan