Beat softened cream cheese until smooth and lump free
Add powdered sugar and vanilla extract, mix until creamy
Mix in marshmallow creme until fully combined
In a separate bowl, whip heavy cream to stiff peaks
Gently fold whipped cream into the marshmallow mixture in batches
Arrange a layer of graham crackers in the bottom of a dish, breaking pieces to fit gaps
Spread a thick, even layer of the cream mixture over the crackers
Repeat layers of graham crackers and cream mixture until all is used, finishing with cream on top
Heat heavy cream until hot and pour over chocolate chips, let sit, then stir until smooth ganache forms
Pour and spread ganache over the top layer evenly
Cover and refrigerate for at least 6 hours or overnight until set
Slice carefully and serve chilled