Mix together the graham crackers and butter. Press down into small cups. Chill.
In a mixer, beat together the cream cheese, sugar, and lemon zest until smooth and creamy. Use the balloon whisk attachment
Add in the lemon, salt, and vanilla. Beat until smooth and creamy.
Pour in the heavy cream and beat until the mixture is doubled in volume.
Pour into the cups over the graham cracker crust. Chill until set. At least 1 hour, preferably 4.
Notes
If you want to make this in a pie pan, you can use the recipe for my graham cracker crust and multiply the filling by 1.5x. You will need to leave the cheesecake to set for a minimum of four hours.