For the best flavor, use a good quality, imported bitter-sweet chocolate. From Bon Appétit.
Bring 3 cups of milk, 1/3 cup water, and sugar to a simmer in heavy large saucepan, stirring to dissolve sugar.
Remove from heat.
Add chocolate and whisk until melted and smooth.
Refrigerate until well chilled, about 4 hours (Can be made one day ahead. Cover and keep refridgerated).
Mix 3/4 cup milk into chocolate mixture.
Working in batches, blend until frothy.
Divide ice among 4 glasses.
Pour Chocolate mixture over and serve.
