In a medium bowl, combine the diced strawberries with sugar (if using) and set aside to macerate for about 10 minutes.
In another bowl, mix the vanilla pudding and whipped topping until well combined and smooth.
In clear cups or dessert glasses, layer the ingredients starting with a layer of crushed chocolate sandwich cookies at the bottom.
Add a layer of the vanilla pudding mixture on top of the cookies.
Next, add a layer of the macerated strawberries, followed by a layer of blueberries.
Repeat the layers until the cups are filled, finishing with a layer of whipped topping.
Garnish with additional berries and a mint leaf if desired.
Chill in the refrigerator for at least 30 minutes before serving to allow the flavors to meld.