In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth.
Gradually add the powdered sugar and vanilla extract, mixing until well combined.
Gently fold in the whipped topping until the mixture is light and fluffy.
In a separate bowl, combine the sliced strawberries, blueberries, and mini marshmallows.
Add the fruit mixture to the cream cheese mixture and fold gently until everything is evenly coated.
Refrigerate the salad for at least 1 hour to allow the flavors to meld.
When ready to serve, layer the cheesecake salad in a large serving bowl or individual cups, alternating layers of the salad and graham cracker crumbs.
Finish with a sprinkle of graham cracker crumbs on top for garnish.