Peel and core the pears and cut in quarters – keep them in acidulated water while preparing to preserve the colour.
Measure the sugar and vinegar into a saucepan and add the spices tied in muslin. Stir over low heat to dissolve the sugar, add the pears and bring to the boil. Simmer gently until the pears are tender but still whole, then draw off the heat. With a perforated spoon lift th