Preheat the oven to 350°F (175°C). Grease a 9×13-inch baking pan.
Combine cake mix, pumpkin puree, eggs, oil, water, and pumpkin pie spice. Beat until smooth.
Pour batter into the prepared pan and bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cake to cool for 10 minutes, then poke holes across the surface using the handle of a wooden spoon.
Whisk together sweetened condensed milk, caramel sauce, bourbon, and vanilla extract.
Pour the bourbon caramel mixture evenly over the cake, allowing it to seep into the holes.
Refrigerate for at least 2 hours.
Beat heavy cream, powdered sugar, and vanilla until stiff peaks form.
Spread whipped cream over the cake and top with toasted pecans, caramel drizzle, and a light dusting of cinnamon.
Slice and serve chilled or slightly cool.