In a bowl, mix graham cracker crumbs, sugar, and melted butter. Press mixture into the bottom of a 9x13 inch baking dish to form the crust.
In a separate bowl, dissolve lemon jello in boiling water. Stir in Greek yogurt or sour cream, cream cheese, powdered sugar, lemon juice, and vanilla until smooth. Fold in cool whip.
Spread the lemon cheesecake mixture over the graham cracker crust.
Prepare lemon pudding by whisking together the instant pudding and cold milk until thickened. Spread over the cheesecake layer.
Top with additional cool whip and garnish with white chocolate curls if desired.
Notes
Chill for at least 4 hours before serving for best results.