Move the oven rack to the middle position and preheat to 350 degrees F.

In the bowl of a stand mixer fitted with a paddle attachment or in a large bowl with a handheld mixer, add the butter and beat on medium speed until lightened in color, about 3 minutes.

Add the flour and walnuts and mix until just combined (the mixture will be crumbly!).

Press the mixture into an even layer in an ungreased 9x13-inch pyrex pan.

Bake for 22-26 minutes, or until the crust is starting to brown around the edges.

Move the pan to a wire rack and cool completely.

In the bowl of a stand mixer fitted with a paddle attachment or in a large bowl with a handheld mixer, add the cream cheese and powdered sugar and beat on medium speed for 1 minute. Add cool whip and beat until combined.

Spread the cream cheese mixture into an even layer over the cooled crust.

In a medium bowl add pudding mix and milk. Whisk until thickened, about 2 minutes.

Pour the lemon pudding over the cream cheese layer and smooth into an even layer.

You should have 2 cups of Cool Whip left in the container, give it a quick stir to loosen it up. Then, spread the Cool Whip evenly over the lemon pudding layer. Sprinkle with chopped walnuts.

Cover the lemon lush with foil and chill in the refrigerator for 2 hours or overnight.

Slice, serve, and enjoy.