Start by lining your 9x9 inch baking dish with parchment paper. This will make it easy to lift out the fudge once it has set. Leave a bit of an overhang on the sides to help with removal.
Using a double boiler or a microwave-safe bowl, combine the semi-sweet and milk chocolate chips. Melt them together until smooth, stirring frequently to prevent burning. If using a microwave, heat in 30-second intervals, stirring in between, until fully melted.
Once the chocolate is melted and glossy, remove it from the heat. Stir in the Nutella until fully incorporated, creating a luscious chocolate-hazelnut mixture.
Gently fold in 1 cup of the mini marshmallows and the chopped graham crackers into the chocolate-Nutella mixture. This adds texture and that familiar smores flavor.
Spread the fudge mixture evenly into the lined baking dish. Sprinkle the remaining mini marshmallows on top for an extra touch of sweetness and visual appeal.
Refrigerate the fudge for at least 2 hours or until fully set. Patience is key here, as this will ensure the fudge holds its shape when cut.
Once the fudge is set, use the parchment paper to lift it out of the baking dish. Cut into squares and serve. Enjoy the ooey-gooey goodness of your homemade Nutella Smores Fudge!
