Heat the dark chocolate in a double boiler placed over simmering water or in the microwave in 30 second intervals. Stir until smooth, do not overheat or chocolate will burn and seize up.
Remove from heat and stir in sweetened condensed milk and vanilla extract. Mixture will be thick and slightly grainy.
Use a spoon or small scoop to portion mixture into desired size for truffles (mine were about 1 tablespoon each). Use your hands to roll into balls. Chill in the fridge while you melt chocolate for dipping.
Melt the milk or dark chocolate (or both in separate bowls) in the microwave or over double boiler.
Dip the truffle balls in the chocolate until completely covered. Use a fork to remove truffles from the melted chocolate, letting excess chocolate fall back into the bowl. Transfer to parchment or wax paper with the help of a toothpick.
Sprinkle with flaky salt and let chocolate set up at room temperature for about 30 minutes.
Store truffles in a cool dry place for 1-2 weeks.
