4 cups sliced fresh plums 1/2 cup sugar 1/4 cup all-purpose flour 1/4 teaspoon salt 1/4 teaspoon ground cinnamon 1 tablespoon lemon juice 1 (9 inch) unbaked deep dish pastry shell | TOPPING: 1/2 cup sugar 1/2 cup all-purpose flour 1/4 teaspoon ground cinnamon 1/4 teaspoon ground nutmeg 3 tablespoons cold butter or margarine |