In a medium saucepan, combine the large marshmallows, pure pumpkin, cinnamon, pumpkin pie spice, and salt. Over low heat, stir the mixture continuously for about 5-7 minutes, or until the marshmallows have completely melted and the mixture becomes smooth and well combined.

Once melted, remove the saucepan from heat and carefully transfer the mixture into a large mixing bowl. Allow it to cool to room temperature for approximately 30 minutes.

After your mixture has cooled, gently fold in the thawed Cool Whip using a spatula until the filling turns a lighter shade of orange.

Take your store-bought graham cracker crust and spoon the fluffy pumpkin filling into the crust, spreading it evenly.

Cover the filled crust with a lid or plastic wrap, and place it in the refrigerator. Allow the pie to chill for at least 8 hours, or preferably overnight.

When ready to serve, remove the pie from the refrigerator and use a sharp knife to slice it into wedges. Top each piece with a dollop of whipped cream before serving.