Pre-heat oven 325 degrees.

In a bowl, mix together butter, flour and 1 cup of chopped walnuts.

Press mixture into the bottom of a 13x9 baking dish.

Bake for 20 minutes or until lightly golden brown.

Let crust cool completely.

Meanwhile, mix together pudding with milk until thick.

Stir in pumpkin puree; spread over cooled crust.

Beat powdered sugar and cream cheese together until fluffy.

Fold in whipped topping.

Spread evenly over pumpkin mixture.

Top with remaining whipped topping.

Garnish with remaining chopped walnuts and sprinkle cinnamon over the top.

Refrigerate for at least 1 hour.