This is a classic French tomato vinaigrette, comprising diced ripe tomatoes, good olive oil, tarragon, basil and one of my very favourite herbs – chervil. The beauty of this sauce lies in its fresh clean flavour and it really needs to be put together shortly before serving. It goes beautifully with simply grilled fish of any variety, especially salmon and very fresh, deliciously oily sardines. It is also very good with grilled beef or lamb.