Instructions

1. Grease the bottom and sides of an 8×8 baking pan with butter. Line the pan with parchment paper, leaving a 2-inch overlap on the sides.
2. In a medium glass bowl, mix together sweetened condensed milk, vanilla, bittersweet chocolate chips, Nutella, and butter.
3. Form a double-boiler by setting the bowl on a medium pot of gently simmering water. The water level should be low enough that the bottom of the bowl does not touch the water. Stir until the chocolate chips are melted and the mixture is smooth.
4. Pour the mixture into the prepared pan and spread the top smooth with a spatula. Refrigerate until the fudge is set.
5. After about 1 hour of chilling, I sprinkled the top with course sea salt. Continue to chill for fudge for another hour (making the minimum time needed to chill 2 hours.)
6. Using the overhanging parchment paper, lift the fudge out. Peel off the parchment paper. Run a knife under hot water, dry it off, and cut the fudge into 3/4-inch squares. Store in the refrigerator in an airtight container.