I once visited kumquat orchards in Israel and the little trees massed with their brilliant orange fruit were a charming sight, like a miniature world. Kumquats have a pleasantly sharp and piquant flavour and the edible skin is quite thin. This is the perfect sauce for serving with roast or grilled duck.
250g (8oz) fresh kumquats, cut in half lengthwise and pips removed
Put the kumquats into a saucepan with the apple juice, and bring to the boil, then simmer gently for about 20 minutes until they are very soft. Stir in the caster sugar, then remove from the heat and stir in the raspberry vinegar.
Put 1tablespoon of water in a cup, add the arrowroot and mix