1/2 cup chopped pecans plus additional pecan halves for garnish, if desired
Cut pound cake horizontally into 3 layers.
Combine milk and pudding in a large bowl; mixing until well blended. Let stand 2-5 minutes or until pudding thickens. Stir in pumpkin and pie spice; mixing until well blended. Fold in whipped topping and chopped pecans.
Frost bottom layer with pumpkin mixture. Place second layer on top and frost with pumpkin mixture. Top with third layer; frost cake with remaining pumpkin mixture.
Top with pecan halves, if desired. Refrigerate at least 1-4 hours, before serving.