In a medium bowl, combine graham cracker crumbs, melted butter, and sugar until evenly moist. Press this mixture into the bottoms of mini dessert glasses and set aside to chill.

In a large mixing bowl, beat together the reduced-fat cream cheese and low-fat vanilla Greek yogurt until smooth. In another bowl, whisk together the sweetened condensed milk and key lime juice, then fold this into the cream cheese blend.

Divide the filling into two portions. Optionally add green food coloring to one portion. Using piping bags, alternate layering the fillings in each mini dessert glass.

Place the assembled mini desserts in the refrigerator for at least 2 hours to chill and set.

Before serving, sprinkle whipped cream on top and add lime zest or extra graham cracker crumbs.