Make the crust
1-In a medium bowl, stir together graham: In a medium bowl, stir together graham cracker crumbs and sugar. Add melted butter and stir until all crumbs are evenly moistened. Press the mixture firmly into the bottom of a 9×13-inch dish. Place in the refrigerator or freezer while you make the filling.

Make the lemon cheesecake layer
2-In a small bowl, dissolve lemon Jell-O: In a small bowl, dissolve lemon Jell-O in boiling water. Set aside to cool to room temperature. You can place it in the fridge to speed up the process.
3-In a large mixing bowl, beat softened: In a large mixing bowl, beat softened cream cheese and powdered sugar until smooth. Add Greek yogurt or sour cream, lemon juice, and vanilla, and mix until combined.
4-Slowly mix in the cooled lemon Jell-O: Slowly mix in the cooled lemon Jell-O.
5-Fold in 2 cups thawed Cool Whip: Fold in 2 cups thawed Cool Whip until the mixture is smooth and creamy.
6-Spread the lemon cheesecake layer evenly over: Spread the lemon cheesecake layer evenly over the chilled crust. Place in the refrigerator or freezer for a few minutes to firm up slightly while you make the pudding layer.

Make the lemon pudding layer
7-In a mixing bowl, whisk instant lemon: In a mixing bowl, whisk instant lemon pudding mix with cold milk until it begins to thicken. Spread the pudding evenly over the lemon cheesecake layer.

Add the topping
8-Spread 3 cups thawed Cool Whip over: Spread 3 cups thawed Cool Whip over the pudding layer.
9-Refrigerate for at least 4 hours, or: Refrigerate for at least 4 hours, or preferably overnight, until completely set.

Garnish and serve
10-To make white chocolate curls, let the: To make white chocolate curls, let the white chocolate bar sit at room temperature so it is not too hard. Use a sharp, thin knife or vegetable peeler to shave curls or shavings from the edge of the chocolate. Sprinkle over the top before slicing and serving.