Combine apples, cherries, lemon rind, juice, and cinnamon; toss well. Spoon mixture into a lightly greased 13- x 9- x 2-inch baking dish
Combine flour, sugar, and salt in a large mixing bowl; cut in butter with a pastry blender until mixture resembles coarse meal. Sprinkle topping over fruit mixture. Bake, uncovered, at 350° for 55 minutes or until apples are tender and topping is golden brown. Serve warm with ice cream, if desired.