Chocolate Stout Donuts

flour1 tablespoon unsweetened cocoa powder2 ½ teaspoons baking powder¾ teaspoons baking soda½ teaspoon salt1 egg, plus 1 egg yolk1 teaspoon vanilla ¾ cup sugar3 tablespoons butter3 ounces of dark chocolate1/3 cup milk½ cup dark beer

butter3 ounces chocolate1 3/4 cup powdered sugar4-5 tablespoons of warm water