Sloes are small, dark wild plums which make a delicious, and slightly sharp, cheese. Wash the fruit and then simmer in very little water until soft. Sieve and weigh the pulp and allow 1lb/500g sugar to each 1 lb/450g of fruit pulp. Stir in sugar over low heat until dissolved and then bring to the boil. Cook gently, stirring well until thick. Pour into small, hot, wide-necked jars, and cover.