Place the chopped chocolate in a medium bowl; set aside.
Heat the heavy cream in a small saucepan over medium heat until it reaches a simmer. Pour over the chopped chocolate and let sit for 2 minutes. Using a rubber spatula, gently stir the mixture, beginning in the center, until all of the chocolate is melted and the mixture is smooth.
Pour into a shallow serving dish and top with the miniature marshmallows. Use a kitchen torch to toast the marshmallows; serve with graham crackers.
Notes
Note: If you don't have a kitchen torch, assemble the dessert in a broiler-proof dish and place under the oven's broiler for a minute or two to toast the marshmallows.Nutritional values are based on one serving