3 cup strong brewed coffee
1 cup milk
4 tbsp sugar
1/2 cup Kahlua or Tia Maria
1/2 cup chilled heavy cream
3 tbsp unsweetened cocoa powder
Bring coffee, milk, and 2 tablespoons sugar just to a simmer in a 3-quart saucepan, then stir in Kahl˙a to taste.
While coffee is heating, beat cream with cocoa and remaining 2 tablespoons sugar in a bowl with an electric mixer until it just holds soft peaks.
Divide coffee among 4 mugs, then top with chocolate whipped cream and chocolate shavings.