Line a muffin tin with 12 muffin liners.
Pulse the graham crackers into crumbs using a food processor or blender.
Add the graham cracker crumbs, melted butter, salt, and brown sugar to a small mixing bowl. Mix well to combine.
Distribute the graham cracker crust mixture into the bottoms of the lined muffin tin, then press it down with the back of a spoon.
Place the pan with the crusts in the refrigerator while you make the cheesecake filling.
In a mixing bowl, whip the heavy cream until stiff peaks form.
In a separate bowl, beat the cream cheese and powdered sugar until smooth. Add the vanilla extract and lemon juice and beat to combine.
Use a rubber spatula to gently fold the whipped cream into the cream cheese mixture until combined and no lumps remain.
Distribute the cheesecake filling evenly into the 12 muffin cups, smoothing out the tops.
Refrigerate the mini cheesecakes for at least 3 hours, or until set.
Store leftover mini cheesecakes in an airtight container in the refrigerator for 4-5 days.