Line your square pan with parchment paper, leaving some overhang on the sides for easy lifting later.
Combine the chocolate chips and butter in a heatproof bowl.
Set the bowl over a saucepan of simmering water, ensuring the bottom doesn’t touch the water, and gently melt, stirring occasionally, until smooth and glossy.
Remove the bowl from heat and stir in the sweetened condensed milk and vanilla extract until fully combined and silky.
Pour the warm, thick mixture into your prepared pan and spread evenly with a spatula, smoothing the surface gently.
Bake in a preheated oven at 160°C (320°F) for about 10 minutes until the top looks set and slightly shiny.
Remove from the oven and let cool at room temperature for about 15-20 minutes; the fudge will start to pull away from the edges and develop a glossy surface.
Transfer the pan to the fridge, uncovered, and chill for at least 2 hours until firm and sliceable.
Once cooled and firm, lift the fudge out of the pan using the parchment overhang and cut into small squares with a sharp knife.
Sprinkle a tiny pinch of sea salt or chili powder on top of each square for an added flavor contrast, if desired.
Serve immediately or store in an airtight container in the refrigerator for up to a week. Enjoy the rich, chewy, and slightly salty bites!
