In a medium bowl, combine graham cracker crumbs, melted unsalted butter, and granulated sugar. Mix until resembling wet sand. Press firmly into a 9x13-inch pan to form crust and set aside.

In a large mixing bowl, pour heavy whipping cream and beat on medium-high until stiff peaks form, about 3-5 minutes. Transfer to another bowl and set aside.

In the same bowl, beat softened cream cheese, confectioners' sugar, and vanilla until smooth, about 2-3 minutes. Fold in half of the whipped cream gently.

Spread cream cheese mixture over the crust, ensuring an even layer. Sprinkle mini marshmallows on top and press them down lightly.

In a microwave-safe bowl, add chocolate chips and milk. Heat in 30-second intervals, stirring until smooth, about 1-2 minutes. Pour over marshmallows.

Spread marshmallow crème over the chocolate layer, covering completely.

Dollop remaining whipped cream over the marshmallow crème and smooth it out.

Sprinkle with crushed graham crackers, chocolate chips, and mini marshmallows if desired. Cover and refrigerate for at least 4 hours or overnight.

Slice into squares and serve chilled, pairing with fresh fruit or chocolate syrup if desired.