Preheat oven to 350 degrees. Prep 3 - 9" or 8" round cake pans with oil and flour, and add circles of parchment on the bottom.
In a great big bowl, add the spice or yellow cake mix, 4 eggs, 1 cup of pumpkin, 1 tsp. pumpkin spice (if using yellow cake mix), milk, oil and eggs. Mix until combined very well. My cake rose higher when I mixed by hand with a fork. Bake for 20-25 minutes. Or until a toothpick inserted comes out clean. Remove cakes from pans and allow to cool. Store at room temperature covered in saran wrap until ready to put together.
With an electric mixer, beat the room temperature cream cheese. Add powdered sugar, rest of the pumpkin (about 3/4 cup), and 1 teaspoon of pumpkin spice. Beat together until combined completely. Add teh cool whip/whipped cream. Fold in gently!
On a microwave safe plate or small skillet, toast the pecans over medium low heat until fragrant. Be careful - they can burn quickly! Set aside 8-10 full size pecans and chop the rest.
Put one cake layer bottom side down on your plate. Cover with one third of the pumpkin whipped cream mixture. Spread evenly. Add one third of the chopped pecans evenly and sprinkle on top. Even out the middle cake layer if needed. Add the second cake layer on top. Spread the second third of cool whip mix. Sprinkle second third of chopped pecans. Add final cake layer upside down so that the flat side is facing up. Spread remaining cool whip mix. Sprinkle pecans and decorate with reserved whole pecan halves. For extra mounds of cool whip like in the photo, fill a pastry bag with cool whip and pipe using a 1M tip.
Store in an air tight container or in plastic wrap. It should be refrigerated until ready to serve.
Drizzle caramel topping right before serving.