Line an 8x8 inch pan with parchment paper or foil, leaving overhang on all sides.
Combine chocolate chips and sweetened condensed milk in a medium saucepan over low heat. Stir constantly until fully melted and smooth, about 5 minutes.
Remove from heat. Stir in peppermint extract, vanilla extract, and salt until fully combined.
Pour into the prepared pan and spread into an even layer.
Immediately scatter crushed candy canes over the top and press them gently into the surface.
Refrigerate for at least 3 hours or overnight. Lift out, peel back lining, and cut into squares with a warm knife.