1. Melt butter and marshmallows in a saucepan over medium heat until smooth and fully combined.

2. Stir in Rice Krispies cereal until evenly coated, then press half of the mixture into a greased 9-inch springform pan to form the base.

3. In a mixing bowl, beat softened cream cheese until smooth, then add powdered sugar and vanilla extract and mix well.

4. In a separate bowl, whip heavy cream until stiff peaks form, then gently fold into the cream cheese mixture.

5. Spread the cheesecake filling evenly over the prepared base layer and refrigerate for 2 hours until firm.

6. Prepare the remaining Rice Krispie mixture or reheat if needed and gently press it over the cheesecake layer.

7. Chill for an additional 30 minutes then slice and serve cold.