Begin by making the tomato sauce. Put the onion into a saucepan with half the oil and let it sweat slowly over a low-medium heat for around 15 minutes until it's soft (do not allow it to colour). If it looks as though it might catch, add a splash of water to the pan
Add the tomatoes and season with salt. Leave to simmer over a low heat for about 45 minutes, until the tomatoes are thick and rich, adding a little water if the level of the liquid gets too low. Remove from the heat
Put the remaining oil in another pan with the garlic and cook over a low-medium heat. When it's almost golden brown, add the basil leaves and stir. Pass the oil through a sieve into the cooked tomato sauce
To make the aubergine and tomato pasta, place the oil in a saucepan over a medium heat and sweat the garlic until golden