Preheat the oven to 350°F. Spray a 9X13 inch baking dish with non-stick cooking spray and set aside.

In a large bowl, mix together the yellow cake mix, pumpkin puree, brown sugar and pumpkin pie spice until combined and smooth but do not over mix.

Transfer the cake batter to the prepared baking dish and spread evenly. Bake the cake for 20 to 25 minutes. An inserted toothpick should come out clean.

Allow the cake to cool for 15 minutes on a wire rack.

Poke holes all over the top of the cake about 1 inch apart and about halfway through the cake.

Evenly pour the sweetened condensed milk over the top of the cake making sure it fills all of the holes.

Chill the cake in the fridge for 30 minutes to allow the sweetened condensed milk to soak into the cake.

Remove the cake from the fridge and carefully spread the whipped topping evenly over the top of the cake.

Sprinkle the toffee bits over the top. Next, drizzle the caramel sauce over the top of the cake.

Finally, place the cake back in the fridge and allow it to chill for a minimum of 3 hours.