Line a square baking pan with parchment paper, leaving overhang for easy removal.
Place a saucepan over low heat, and melt the butter along with the chocolate chips, stirring constantly until the mixture is glossy and completely smooth, filling your kitchen with a rich, chocolatey aroma.
Remove the saucepan from heat, then stir in the granulated sugar and vanilla extract, mixing until the sugar dissolves and the batter thickens slightly, about 2 minutes.
Pour in the heavy cream and stir well, creating a smooth, velvety batter that’s thick but pourable, with a shiny, luscious appearance.
Incorporate the cocoa powder gradually, stirring until fully blended and the mixture turns a deep, uniform chocolate color.
Pour the batter into the prepared pan and use a spatula to spread it evenly, smoothing the surface as you go, until it’s level and glossy.
Sprinkle a pinch of sea salt flakes on top for that perfect salty-sweet contrast, pressing them lightly into the surface.
Place the pan in the fridge and chill for at least 2 hours until the fudge is firm and set.
Once chilled, lift the fudge out of the pan using the parchment overhang and transfer to a cutting board.
Use a sharp knife to cut the fudge into squares, wiping the blade clean between cuts for neat edges.
Arrange the fudge bars on a plate and let sit at room temperature for 5 minutes before serving to soften the edges for a perfect bite.
