Preheat your oven to 325°F (160°C). Grease the springform pan and line the bottom with parchment paper for easy removal.

In a saucepan over low heat, melt the butter. Once melted, add the mini marshmallows and stir until completely melted and smooth.

Remove the pan from heat and mix in the Rice Krispies cereal until well-coated. Press the mixture firmly into the bottom of the prepared springform pan to form the crust. Set aside to cool.

In a large mixing bowl, beat the softened cream cheese with an electric mixer until creamy.

Gradually add the granulated sugar and vanilla extract, mixing until smooth.

Add the eggs one at a time, mixing well after each addition, until fully incorporated.

Pour the cheesecake batter over the cooled Rice Krispie crust in the springform pan, smoothing the top with a spatula.

Bake in the preheated oven for 20 minutes, or until the edges are set but the center is slightly jiggly.

Remove from the oven and let cool at room temperature for about 1 hour, then refrigerate for at least 4 hours, or until fully set.

Before serving, sprinkle the top with mini marshmallows. In a small saucepan, melt chocolate chips with vegetable oil over low heat, stirring until smooth. Drizzle the melted chocolate over the cheesecake and marshmallows.