In a small mixing bowl combine pie crust mix and 1/4 cup sour cream; stir till moistened. Turn dough onto a generously floured surface. Knead about 12 times, or till dough is firm enough for easy handling. Spray a 10 inch round tart pan with a removable bottom with cooking spray. Press dough evenly onto the bottom and up the sides of the pan.
In another bowl beat egg slightly. Stir in almonds, corn syrup, and almond extract. Pour mixture into tart shell, spreading evenly. Bake at 375 degrees F ( 190 degrees C) for 25 to 30 minutes, or till crust is brown and filling set. Cool in pan on a wire rack.
In a small mixing bowl, stir together remaining 3/4 cup sour cream and cream cheese. Spread atop the almond mixture.
Using a cheese slicer or a vegetable peeler, thinly slice the peeled melon and mango or papaya. Arrange the fruit slices atop the filling. Cover and chill for up to 2 hours.
Before serving, melt the apple jelly over medium heat in a small saucepan. Brush onto melon and mango. Cut into squares or wedges, and serve immediately.