Place the graham cracker crumbs in a medium bowl along with the crushed pecans, sugar, pumpkin pie spice and melted butter; then mix all ingredients to combine.

Transfer the mixture into an 8x8 dish casserole dish and press to flatten into an even layer (you can press down using the bottom of a glass or measuring cup). Place to chill in the freezer for 30 minutes.

To make the second layer; combine the softened cream cheese, powdered sugar, vanilla extract in a large mixing bowl using a hand mixer. Mix until light and fluffy with no more lumps, then place aside.

Place the heavy whipping cream in a chilled medium bowl and whip it on high using a hand mixer until stiff peaks develop; for about 5 minutes.

Gently mix the heavy whipping cream with the cream cheese mixture using only a rubber spatula. Once combined, take half of the mixture and spread on top of graham cracker crust. Put the other half aside and place the casserole dish in the fridge while tackling the last step.

Add the pumpkin puree, brown sugar, and pumpkin pie spice to the remaining cream cheese/whipping cream mixture and gently combine together. Once combined, take out the mixture and spread in the dish to form the third layer.

To make the last layer of this dessert, layer the cool whip on top, then sprinkle the rest of the chopped pecans and lightly coat with cinnamon if desired.