Line an 8x8-inch baking pan with parchment paper, leaving some overhang for easy removal.

In a medium saucepan, combine chocolate chips, sweetened condensed milk, and butter over low heat.

Stir constantly until the chocolate and butter are fully melted and the mixture is smooth.

Remove from heat and stir in vanilla and salt until well combined.

Pour the mixture into the prepared pan and smooth the top with a spatula.

Refrigerate for at least 2 hours or until firm.

Lift the fudge out using the parchment paper and cut into squares.