Combine flour and walnuts in a bowl. Cut in the butter until mixture is the consistency of fine crumbs. Press into a 13 x 9 inch baking pan. Bake crust at 350 degrees for 15 minutes or until golden brown. Let cool.
Combine sugar, cream cheese, and half of the carton of whipped topping in a bowl, beating until smooth. Spread over crust.
In 2 separate bowls, combine each pudding mix with 1.5 cups of milk and mix until the pudding is at a soft serve consistency. Spread chocolate pudding over cream cheese mixture, then vanilla pudding over chocolate pudding layer.
Spread remaining whipped topping over vanilla pudding layer and chill until ready to serve. May be garnished with chocolate curls, chopped nuts, or both.