In a large bowl, add the thawed 8-ounce package of whipped topping (like Cool Whip), 15-ounces of canned pumpkin puree, and 2 teaspoons pumpkin pie spice.
Empty the dry contents of the 3.4-ounce package of Instant Vanilla Pudding and stir until everything is well combined.
Fold in 1-1/2 cups of mini marshmallows and stir until the marshmallows are evenly distributed throughout the pumpkin fluff dip.
Serve in a bowl with graham crackers, Gingersnaps, or apple slices to use as dippers.
For a nice presentation, add a dollop of whipped topping on top of the Pumpkin Fluff and sprinkle with cinnamon just before serving.
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Notes
Be sure to buy pumpkin puree and not pumpkin pie filling. That is very important for this recipe to work.
Be sure to use the small package of instant pudding, which is 3.4 ounces. If you don't want to use vanilla instant pudding, cheesecake pudding works well also.
If you don't have pumpkin pie spice, then see the blog post above for a substitute for it. You can easily make your own pumpkin pie spice to use in this recipe.
It is very important that the whipped topping be thawed out. Frozen whipped topping won't work. Be sure to plan ahead to give yourself time to thaw out the whipped topping.
If you don't have mini marshmallows, then leave them out of the recipe. There is no need to substitute anything else.