Heat a skillet over medium heat.

Beat the egg and milk together in a pie plate or shallow dish. Pour the graham cracker crumbs in a second pie plate or shallow dish.

Spread Nutella on both slices of bread. Top one slice with mini marshmallows and then put the other slice of bread on top, Nutella side down. Squish it together a bit.

Place the sandwich in the egg mixture and turn to coat. Remove from the egg mixture and place in the graham cracker crumbs, turning the sandwich to coat each side with crumbs.

Place the sandwich on the skillet and cook until lightly browned and the marshmallows are melted. Let sit for a few minutes before cutting in half. Enjoy!