Combine crust ingredients, and press into a buttered 9x13 baking dish. Bake at 325 degrees for 20 minutes, then let cool.
In a large bowl, beat the condensed milk and cream cheese together until smooth. Beat in the lemonade concentrate, and fold in the Cool Whip. If you want to, you can add a drop or two of yellow food coloring, but that's totally optional! When the crust is completely cool, spread this cream cheese mixture on top.
Whip the heavy cream until soft peaks form, then add the powdered sugar. This is really to taste--so start with 1/4 c. and then add a little more if you want to. The dessert already is pretty sweet, so in this case less is probably more.
Refrigerate until ready to serve, then sprinkle with grated lemon zest!