2. Peel and finely slice the onion and garlic. If using fresh, cut the tomatoes in half, then roughly chop them or carefully open the tins of tomatoes.
3. Put a saucepan on a medium heat and add 1 tablespoon of olive oil and the onion, then cook for around 7 minutes, or until soft and lightly golden.
4. Stir in the garlic and basil stalks for a few minutes, then add the fresh or tinned tomatoes and the vinegar.
5. Season with a tiny pinch of salt and pepper, then continue cooking for around 15 minutes, stirring occasionally.
6. Stir in the chopped basil leaves, then reduce to low and leave to tick away. Meanwhile…
7. Carefully fill a large pot three-quarters of the way up with boiling water, add a tiny pinch of salt and bring back to the boil.
8. Add the spaghetti and cook according to packet instructions – you want to cook your pasta until it is al dente. This translates as 'to the tooth' and means that it should be soft enough to eat, but still have a bit of a bite and firmness to it. Use the timings on the packet instructions as a guide, but try some just before the time is up to make sure it's perfectly cooked.
9. Once the pasta is done, ladle out and reserve a cup of the cooking water and keep it to one side, then drain in a colander over the sink and tip the spaghetti back into the pot.
10. Stir the spaghetti into the sauce, adding a splash of the pasta water to loosen, if needed.
11. Serve with the reserved basil leaves sprinkled over the top and use a microplane to finely grate the Parmesan cheese, then sprinkle over.
Read more at http://www.jamieoliver.com/recipes/pasta-recipes/classic-tomato-spaghetti/#G3z8LWlDo6looMPX.99