Set aside a tablespoon or so of the chopped pecans for the topping. Preheat the oven to 350° F.
Mix the melted butter and flour in a medium bowl. Add the chopped pecans and press into a 9 by 13-inch pan. Bake for 25 minutes, or until light golden brown. Refrigerate until cool.
Beat softened cream cheese and powdered sugar in a medium bowl until smooth. Add one cup of Cool Whip and beat until well incorporated. Spread over cooled crust.
In a large bowl or measuring cup, whisk together the pudding mix and cold milk until it begins to thicken, a few minutes. Spread on top of cream cheese layer.
Carefully dollop the rest of the Cool Whip over top of the pudding mixture and smooth to the edges. Sprinkle with the rest of the chopped pecans. Cover and refrigerate until set, 2-3 hours.
"Robert Redford" will last in the fridge for 3-4 days, but the chocolate will begin to bleed into the Cool Whip the longer it sits.