Preheat the oven to 375 degrees. Prepare a large baking sheet with parchment paper or aluminum foil.
On a surface lightly dusted with flour, roll out puff pastry slightly and transfer to baking sheet. With a knife, gently trace a 1-inch border around the edge of the puff pastry, careful not to cut all the way through. Brush beaten egg on the outside border and sprinkle with granulated sugar. Bake for 12-14 minutes, or until golden and puffed.
Remove from oven. With your hands in oven mitts, gently flatten the center of the pastry. Cool at room temperature for about 20 minutes.
While cooling, make the cream cheese mixture. Beat cream cheese with an electric mixer until smooth. Add Cool Whip, lemon zest and 2 Tablespoons powdered sugar, beating again until fluffy and smooth. If pastry is not cooled yet, refrigerate until ready to use. Spread the mixture evenly within the border of the cooled pastry sheet.
Arrange your fruit in desired pattern on top of pastry, and sprinkle with remaining 1 Tablespoon powdered sugar. If desired, sprinkle with chopped mint. Slice into 6 squares and serve. Refrigerate leftovers up to 2 days.