Using a fork, combine the graham cracker crumbs, brown sugar, and melted butter in a small bowl. Mix until graham cracker crumbs are well moistened. Press the graham cracker mixture into individual 4-ounce jars. Set aside.
Using a stand mixer or hand mixer, beat together the cream cheese, granulated sugar, and vanilla until creamy. Add the sweetened condensed milk and lemon juice and mix until just combined.
Spoon the cheesecake mixture into jars with the graham cracker crusts, leaving room at the top for the topping.
Cover the jars with their lids or plastic wrap and place in the freezer for 15 minutes. Remove from the freezer and store in the refrigerator until ready to serve.
When ready to serve, add your topping of choice and enjoy!