In a medium saucepan, sprinkle gelatin over 1/4 cup cold water, let soften 5 minutes. Add heavy cream and place over low heat. Add sugar, chocolate, espresso powder, and salt. Whisk until chocolate has melted, espresso powder is dissolved, and mixture is well combined, about 2 minutes.Advertisement
Whisk in milk and strain mixture into a large measuring cup (for easy pouring). Divide evenly among six 6-ounce coffee cups or custard cups. Refrigerate until set, at least 3 hours. Serve with a dollop of whipped cream, if desired.