In a medium mixing bowl, combine graham cracker crumbs, melted butter, and sugar, stirring until well combined. Set aside.

In a large mixing bowl, use a mixer to beat cream cheese until smooth. Add sweetened condensed milk and vanilla, mixing thoroughly.

To assemble the parfaits, begin with a small layer of the cheesecake mixture, followed by a layer of graham cracker crumbs (using about half, while reserving the remainder for the next layer), then add a layer of chopped strawberries. Follow with another layer of cheesecake mixture, evenly distributing the rest of the mixture among the cups. Finally, top with the remaining graham cracker mixture.

Top with whipped cream or Cool Whip and additional fresh strawberries, if desired.