GRAHAM CRACKER CRUST: Line 2 muffin tins with 24 standard cupcake liners.
In a medium bowl, combine graham cracker crumbs, sugar and melted butter, stir until well combined. Spoon about 1 tablespoon into each cupcake liner. Smash the crumbs down using the bottom of a small cup or shot glass; set aside.
CAKE: Preheat oven to 350 degrees. In a large bowl, using a hand mixer beat all ingredients until just combined. Use a medium-sized cookie scoop to fill each cupcake liner about 3/4 full. Bake for 18-20 minutes or until a toothpick comes out clean. Let cool completely before filling with Nutella.
FILLING: Core a hole in the center of each cupcake fill with about 1 tablespoon of Nutella. Place the cake plug back over the filling.
MARSHMALLOW FROSTING: Place egg whites, sugar, and cream of tartar in the heatproof bowl of a stand mixer. Set over a saucepan with simmering water. Whisk constantly until sugar is dissolved and whites are warm to the touch about 3 to 4 minutes.
Transfer the bowl to the stand mixer fitted with the whisk attachment, and beat, starting on low speed, gradually increasing to high, until stiff, glossy peaks form about 5 to 7 minutes. Add vanilla, beat until combined, use immediately.
Fill a piping bag fitted with a 1M tip with marshmallow frosting. Pipe each cupcake with frosting and then lightly toast with a kitchen torch. Top with a graham cracker piece and a mini Hershey’s milk chocolate bar.