Measure water into a 2-quart sauce pan. Add sugar, cocoa and salt. Heat water over medium heat. Stir mixture until cocoa dissolves completely. Gently bring mixture to a boil. Reduce the heat to a fast simmer and simmer it for about 5 minutes. Finally add the evaporated milk and stir to blend. Reheat briefly, but don't boil. Pour the hot chocolate into small mugs.
This recipe makes 4 6-ounce size servings.
I added a spoonful of whipped topping on the top of each filled mug. It was delicious!