Bake pastry shells according to package directions. Cool completely.
Whisk milk and pudding mix using a hand held blender or a stand mixer for 2 minutes on medium-high speed. Combine the pumpkin puree and spices; stir into the pudding. Fold in 1/2 cup (125 mL) of the whipped topping.
Fill a piping bag with the filling or use a small spoon to fill the patty shells. Top each with a dollop of whipped topping and garnish with chopped pecans and/or small gingersnap cookies.