Grease an 8x8 baking dish with butter or shortening. Set aside.

Crust: Add the ginger snap cookies into a food processor, and blend at high speed until the cookies are finely chopped, about 30 seconds.

Slowly pour in the melted butter while the food processor is running at low speed. The mixture is ready when the crumbs pull away from the sides of the food processor.

Pour the crumbs into the prepared baking dish, and firmly press them into an even layer in the base. Place in the freezer for at least 20 minutes.

Cream Cheese Layer: In a large or medium mixing bowl, add the softened cream cheese and sugar. Beat at medium speed with an electric hand mixer until the cream cheese is smooth, making sure there are no lumps.

Fold in the whipped topping with a spatula until evenly distributed.

Spread the cream cheese mixture over the frozen crust. Chill in the refrigerator for 1 hour.

Pumpkin Layer: Add the instant vanilla pudding mix into a large bowl. Pour in the milk, and whisk until completely mixed and the pudding thickens.

Add the pumpkin puree and pumpkin pie spice, and whisk until smooth.

Fold in the whipped topping until well mixed, then spread over the cream cheese layer in the baking dish. Chill for another 1 hour.

Whipped Cream Topping: In a medium mixing bowl, combine the heavy whipping cream and powdered sugar. Beat at medium-high speed with an electric hand mixer until stiff peaks are formed, about 5 minutes.

Spread the whipped cream over the pumpkin layer, cover with foil or plastic wrap, and chill in the refrigerator for at least 4 hours, but overnight is best.

Sprinkle with cinnamon, and serve chilled.