In a mixer, cream together cream cheese, butter, powdered sugar, vanilla extract, and lemon essential oil. Mix for at least a minute scraping the sides to make sure to integrate all the ingredients.
Add 2 teaspoons of lemon juice and mix. The mixture should be about the consistency of frosting. Add another teaspoon of lemon juice if it's too dry and thick.
Switch mixer to high speed and whip for one minute until light and fluffy.
Spoon the cheesecake mixture into the shells.
Refrigerate at least an hour before serving. Garnish with fruit or whipped cream.