– Using a hand held or stand mixer, beat cream cheese, lemon zest and juice, vanilla extract, powdered sugar, and heavy cream until creamy and lump free.
– Pour lemon mixture into prepared graham cracker crust and smooth the top.
– Cut the extra lemon into crosswise slices. Cut each slice into quarters and use to top the pie.
– Refrigerate for at least an hour.
– Slice and serve with a dollop of whipped cream, if desired.