In a large chilled mixing bowl, beat heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form.
In a separate bowl, stir the pumpkin puree with pumpkin pie spice and cinnamon until smooth.
Gently fold the pumpkin mixture into the whipped cream using a spatula until well combined and uniform in color.
Spread a thin layer of the pumpkin cream onto the bottom of a 9x13 inch rectangular baking dish.
Arrange a single layer of graham crackers over the cream, breaking pieces to fill any gaps.
Spread approximately one-third of the remaining pumpkin cream evenly over the crackers.
Repeat the layers of graham crackers and pumpkin cream two more times, finishing with a smooth cream layer on top.
Cover the dish with plastic wrap and refrigerate for at least 4 hours, or ideally overnight, until the crackers have softened.
Before serving, drizzle with caramel sauce and sprinkle with chopped pecans.