Line a 10x8-inch baking dish or sheet pan with parchment paper.
Arrange the graham cracker sheets in a single layer to cover the bottom of the pan, breaking them as needed to fit.
Melt the chocolate bars in the microwave in 20-second intervals, stirring between each interval until smooth.
Pour the melted chocolate over the graham crackers and gently spread it into an even layer.
Add marshmallow fluff and spread gently over the melted chocolate and graham crackers.
Broil s'mores bark in oven for 5 minutes or until marshmallows are charred to your desire! Watch out this happens really fast!
Refrigerate for 1–2 hours, or until the chocolate is completely set.
Lift the bark out of the pan using the parchment paper, then cut or break into pieces and serve.