Heat 1 cup whole milk in a heavy saucepan over medium-high heat to 180° or until tiny bubbles form around edge (do not boil). Remove from heat, and add the cocoa, stirring with a whisk until cocoa dissolves. Cool to room temperature.
Combine 1 cup whole milk, condensed milk, vanilla, evaporated milk, and salt in a blender, and process until smooth. Add cocoa mixture; blend well. Pour mixture into the freezer can of an ice-cream freezer; freeze according to manufacturer's instructions.