1.    Prepare the Crust: Preheat your oven to 325°F (163°C). In a medium bowl, mix the graham cracker crumbs, sugar, and melted butter until well combined. Press the mixture firmly into the bottom of a 9-inch springform pan to form an even layer. Bake for 10 minutes, then set aside to cool.
2.    Make the Cheesecake Filling: In a large mixing bowl, beat the cream cheese and sugar together until smooth and creamy. Add in the vanilla extract and mix. Then, add the eggs one at a time, beating on low speed until just combined. Be careful not to overmix! Fold in the sour cream and heavy cream until fully incorporated.
3.    Bake the Cheesecake: Pour the cheesecake filling over the cooled crust, spreading it out evenly. Bake in the preheated oven for 50-55 minutes, or until the center is just set and a little jiggly. Turn off the oven and let the cheesecake cool in the oven with the door slightly open for 1 hour. This helps prevent cracking!
4.    Prepare the Topping: After the cheesecake has cooled, sprinkle the mini marshmallows evenly over the top. Use a kitchen torch to toast the marshmallows until golden brown and gooey (you can also use the oven broiler, but keep a close eye on them!).
5.    Finish with Chocolate: Melt the chocolate chips with the heavy cream in a microwave-safe bowl in 20-second intervals, stirring in between until smooth. Drizzle the melted chocolate over the toasted marshmallows.
6.    Chill and Serve: Let the cheesecake chill in the refrigerator for at least 4 hours or overnight before serving. Slice, serve, and watch it disappear!