Roughly chop the tomatoes (peel and seed them first if you like, but we prefer not to). Mix with the rest of the ingredients in a large bowl, cover, and leave to sit at room temperature for 1 to 2 hours; alternately, mix the ingredients in a saucepan and simmer the sauce very slowly over low heat for 30 minutes.
Taste and adjust the seasoning, remove the cloves of garlic, and serve warm or room temperature, over fish, pasta, chicken, or anything else summer throws at you.