Heat half the oil in a deep frying pan over a high heat. Add the prawns and half the garlic. Fry for 2–3 minutes or until the prawns turn pink. Tip onto a plate and set aside.
Reduce the heat to medium. Add the remaining oil, the rest of the garlic and the chilli. Fry for 2 minutes. Add the tomato purée and chopped tomatoes, bring to the boil, then reduce the heat to a gentle simmer and cook for 15 minutes.
Meanwhile, cook the pasta in a pan of salted water according to the packet instructions.
Drain the pasta, reserving the cooking water. Add the pasta to the sauce with a ladleful of the reserved cooking water and toss together to coat the pasta. Return the prawns to the pan, add the basil and toss everything together.
