In a saucepan over medium heat, combine the milk, butter, sugar and 1 square baking chocolate until smooth.  Heat on medium-high, until steaming hot. The cook times will vary by kitchen, so be alert to avoid burning your mixture. Remove from heat and add the liqueur and vodka, stirring for about 30 seconds to ensure that all ingredients mix well.
Serve in espresso cups or shot glasses garnished with whipped cream and chocolate shavings. For a really special touch, melt an additional 1/4 square of chocolate in the microwave until barely melted and dip the edges of the cups or glasses to form a chocolate ring. Allow these to cool and harden before pouring the drinks.

This recipe will yield about 16 individual servings.