1. Heat chocolate and water in 1.
2. 5-quart saucepan, stirring constantly, until chocolate is melted and mixture is smooth.
3. Stir in sugar and salt. Heat to boiling; reduce heat.
4. Simmer uncovered, stirring constantly, 4 minutes.
5. Stir in milk; heat just until hot (do not boil).
6. Beat with hand beater until foamy. Serve immediately.