01 - In a small saucepan over medium-low heat, combine whole milk and heavy cream; warm until steaming without boiling.
02 - Add finely chopped dark chocolate and sugar to the warmed milk mixture, stirring continuously until fully melted and smooth.
03 - Remove the saucepan from heat and stir in pure vanilla extract until evenly blended.
04 - Pour the hot chocolate into four small shot glasses or espresso cups.
05 - Top each shot with whipped cream, chocolate shavings, or a pinch of sea salt if desired and serve immediately.