In the bowl of an electric mixer, whip the cream until stiff.
Remove from the mixer and set aside. (No need to wash the bowl before continuing.) Add the lemon pie filling and cream cheese to the mixer and beat until smooth. Add the vanilla extract, food coloring (if using) and powdered sugar and beat until combined.
Using a rubber spatula, add the whipped cream into the cream cheese mixture, slowly (do it in batches), until its fully incorporated. Set aside.
To make the crumbs, combine the graham cracker crumbs, sugar and melted butter or margarine.
To assemble the cups:
Place a small amount of the crumbs on the bottom of a cup. Pipe the mousse over the crumbs to fill the cup, then add more crumbs on top.
Serve chilled.
Recipe by Overtime Cook at https://overtimecook.com/2013/05/12/no-bake-lemon-cheesecake-mousse-cups/