Preheat oven to 300° F. In a heavy saucepan stir together the egg whites, sugar, condensed milk, salt, vanilla and coconut. Sift in cocoa and stir the mixture until it is combined well. Cook the mixture over moderate heat, stirring constantly, for 5 minutes. Increase the heat to moderately high and cook the mixture, stirring constantly, for 3 to 5 minutes more, or until it is thickened and begins to pull away from the bottom and side of the pan. Transfer the mixture to a bowl, let it cool slightly at room temperature, then chill completely before baking.
Drop heaping teaspoons of the batter 2 inches apart onto greased or parchment-lined baking sheets and bake the macaroons on centre rack of the oven for 20 to 25 minutes. Transfer the macaroons to a cooling rack.
Macaroons will keep up to 10 days in an airtight container.
Yield: 30 macaroons.