Heat milk in a small pan over moderate heat until it comes to a boil. In a blender or food processor, combine egg, 2 tablespoons of sugar, espresso powder, a pinch of salt, semisweet chips and whiskey using the low setting. Pour in boiling milk in a slow stream. The hot milk will cook the egg and melt the chocolate. Process or blend 1 minute, until smooth. Spoon into teacups or champagne glasses and chill.
When ready to serve, whip cream until soft peaks form, about 1-2 minutes. Sprinkle in remaining tablespoon of sugar and combine.
Top chocolate-filled teacups with whipped cream. Place cups on saucers and serve with teaspoons.