Mix the graham cracker crumbs, cinnamon, sugars, and butter until it's like wet sand. Press into a pie plate and bake for 8-10 minutes. Set aside to cool completely.
1 Cup Graham Cracker Crumbs, 1 teaspoon Cinnamon, 1 Tablespoon Brown Sugar, 1 Tablespoon Sugar, 4 Tablespoons Butter
In a medium saucepan, combing the cinnamon, pumpkin, marshmallows, and pumpkin pie spice over medium-low heat, stirring consistently until smooth and all marshmallows are melted.
1/4 teaspoons Cinnamon, 1 Cup Pumpkin Puree, 1 Bag Marshmallows, 1/4 teaspoons Pumpkin Pie Spice
Chill the mixture in the refrigerator until cooled, about 30-60 minutes.
Whip the whipping cream with a handheld mixture until soft peaks form. Set aside.
1 Cup Heavy Cream
Pull the pumpkin mix from the fridge and using a handheld mixer, beat the mixture until fluffy, about 1 minute.
Fold the whipped cream in gently with a rubber spatula and then carefully fill the pie.
Chill 2 hours in the fridge.
Notes
This pie will keep for 3-4 days in the refrigerator.