In a large saucepan combine the chocolate and sugar with the hot water.
Bring to a boil, stirring for 2 minutes.
Add milk, & continue heating.
When hot, beat in vanilla with a rotary egg beater or whisk.
Remove from heat.
Chill, then pour into a punch bowl over ice cream
For sparkle, add club soda.
Top with whipped cream and dust with cinnamon.
Yield: 12 servings.