Put the oil and garlic in a saucepan over medium heat. When you can smell the garlic and it has flavoured the oil, add the tomatoes. Add a good pinch of salt and some pepper and bring to the boil. Lower the heat and cook uncovered for about 15–20 minutes, until the tomatoes have all merged with the oil into a sauce. Add the basil and a few drops of hot water towards the end of the cooking time if it looks as if it needs it. If you like, purée the sauce until smooth, taking out the garlic clove first.
Meanwhile, cook the pasta in boiling salted water, following the packet instructions. Drain the pasta and stir through most of the sauce. Divide among four serving bowls and spoon the rest of the sauce on top. Drizzle with a little olive oil, if you like, and serve with grated parmesan.