To make the crust, use a food processor to grind graham crackers into crumbs. Stir in the melted butter, then divide crust evenly between serving jars or glasses. Set aside.
Using a hand mixer or a stand mixer fitted with the paddle attachment, beat the cream cheese for a few minutes until smooth. Mix in the condensed milk and continue beating until combined.
Divide the filling evenly among the serving jars or glasses, layering it right on top of the crust. Top with a layer of dulce de leche, if using. Chill in the refrigerator for at least 4 hours, or overnight.
Notes
This recipe yields about 28 ounces total. While I opted to make these in two 14-ounce glasses, I still consider it to be four servings because one jar is simply too rich to be a single serving. You can easily split this up among smaller servings.
Be sure to use full-fat blocks of cream cheese for best results.