Using a mixer on medium speed, beat the cream cheese until creamy. Slowly mix in the powdered sugar and then add in heavy cream and mix until combined.
Line a baking sheet with aluminum foil. Spray with non-stick cooking spray or grease foil with butter. Spread out the entire bag of marshmallows into a single layer on to of foil.
Broil marshmallows in the oven for 1-2 minutes or until tops are golden brown. Watch carefully as times vary by oven and marshmallows will burn quickly.
Remove marshmallows from the oven and let cool slightly. Using a spoon or spatula, scrap the marshmallows up and place into the dip mixture.
Mix on medium speed until the marshmallows are incorporated into the dip mixture. Some pieces of marshmallow will remain which is OK.
Break up Hershey chocolate bars and place in a microwave safe bowl. Microwave on 50 percent power in 30 second increments. Stirring each time until chocolate is melted.
Add a layer of the dip into a serving dish or bowl. Add a little bit of the melted chocolate on top of the dip and use a butter knife to swirl together. Repeat with another layer of dip and chocolate.
Optionally, top with additional toasted marshmallows.
Serve with fresh fruit or graham crackers.