In a large bowl, beat the softened cream cheese, lemon zest and juice, and 1/4 cup of powdered sugar.
In a separate bowl, add the remaining 1/4 cup powdered sugar and the heavy whipping cream. Beat until soft peaks form.
Add about 1 cup of the whipped cream to the cream cheese mixture, and beat until blended. Spoon the cream cheese layer over the graham cracker crust, smoothing it with a spatula or the back of a spoon.
Refrigerate for about 30 minutes. Then, spoon the lemon curd on top, smoothing it carefully over the cream cheese layer.
For best results, refrigerate another 30 minutes before adding the whipped cream as the final layer.
Cover the dish with plastic wrap, and refrigerate for at least 2 hours, and preferably overnight to allow it to set firmly before slicing.