Blackberry Curd

Wash blackberries and peel, core, and chop apples. Place in a saucepan and cook gently for about 15 minutes or until really soft. Rub through a sieve and put pulp in a basin or in the top of a double saucepan. Add lemon juice, butter, and sugar. Stand basin over a saucepan of hot water and cook gently until sugar has dissolved, stirring occasionally. Beat eggs well and add to fruit mixture. Continue to cook for about 30 minutes or until it thickens. Pour into hot jam jars and cover as for jam. Refrigerate.