Blanch the tomatoes in boiling water for 30 seconds, refresh in cold water and peel. Cut in half and scrape out the seeds and watery centre, then cut the flesh into 5-mm / ¼-inch dice.
Put into a bowl with the garlic, parsley, chervil, coriander and tarragon Add the oil, season and stir. Leave to mature for an hour or so.
Stir again before serving. To serve hot, warm gently over