Chocolate-hazelnut spread (Nutella) gives this fudge a smooth texture and luscious nutty flavor. The recipe comes from Annie Marshall of the Indianapolis-based blog Annie's Eats.
Place the hazelnuts in a 15x10x1-inch baking pan. Bake in a 250° oven for 20 minutes until lightly toasted and the skins have cracked. Transfer the hazelnuts to a clean kitchen towel. Fold half of the towel over the top of the hazelnuts and roll them around gently to help remove the loosened skins. Transfer the skinned hazelnuts to a cutting board and chop coarsely.
Line an 8x8x2-inch baking pan with foil. Butter the foil lightly; set aside. Set a heatproof bowl on a pot that has a few inches of simmering water (do not boil). In the bowl, combine the sweetened condensed milk, vanilla, chocolate, chocolate-hazelnut spread, butter, and 1/2 teaspoon salt. Heat, stirring occasionally, until the mixture is melted and smooth.
Remove the bowl from the heat. Add the toasted hazelnuts and dried cherries to the bowl and fold in until evenly combined. Spread evenly into the prepared baking pan. Let cool a few minutes, then sprinkle lightly with additional sea salt. Cover and refrigerate until firm, about 3 to 4 hours.
Use the foil to lift the fudge from the pan. Remove and discard the foil. Use a large chef's knife to slice the fudge into 64 1-inch squares. Store in an airtight container.