Wash apricots. Cover with water. Simmer 40 minutes, or until tender and water is evaporated. Beat until smooth. Cool. Cream butter and sugar. Add well-beaten egg yolks, cream, and apricots. Fold in stiffly beaten egg whites. Pour into baked pastry shell. Bake in moderate oven (400 F) until firm. If desired, dried peaches, prunes, or apples may be substituted for apricots.