Collect about 500g crab apples, wash them but don’t peel or core them. Cut large ones in half. Put the crab apples in a pan with vinegar and sugar at a rate of 1 part vinegar: 3 parts crab apple: 3 parts sugar with a good pinch of ground ginger, 4 cloves and a cinnamon stick.
Stir to dissolve the sugar and simmer until the apples are just soft but still in one piece.
Transfer the apples to jars, leaving the liquid in the pan. Remove the clove and cinnamon stick, boil the syrup until it’s reduced by about half and then pour over the apples and seal the jars.
Keep the crab apples for a couple of months before you use them, by which time the apples will have absorbed the syrup to make an almost candied fruit.