In a large saucepan, bring 6 cups milk to a boil over medium-high heat; remove from the heat. Whisk in 6 ounces coarsely chopped bittersweet chocolate, 2 tablespoons brown sugar, 1/8 teaspoon cayenne pepper and a pinch of salt. Stir in 1 cup chocolate liqueur. Serve hot.
The Do's and Don'ts of Cooking with Chocolate