In a medium saucepan heat the milk on medium low heat for about 5 minutes. (See note)
While the milk is heating up chop the chocolate and set aside.
After 5 minutes add the chopped chocolate, cocoa powder, and sugar. Mix until the chocolate is melted and the sugar has dissolved. Cook for another 2 minutes.
Turn off the heat and add the coffee liqueur. (See note)
Pour the hot chocolate into 8 ounce cups or mugs top with a dollop of cool whip and add your favorite treat. (See note) Enjoy!