Chill the brewed coffee until very cold.
Add coffee, milk, chocolate syrup, cocoa, sugar, vanilla, and salt to a blender.
Blend with half the ice until smooth and frothy.
Add the remaining ice and blend again until thick and slushy.
Taste and adjust sweetness or chocolate to preference.
Pour into two glasses, top with whipped cream, and drizzle with extra syrup. Serve right away.