Preheat oven to 325 degrees F. Line two cookie sheets with parchment paper; set aside. In a large mixing bowl beat egg whites, vanilla, cream of tartar, and salt with an electric mixer on high speed until soft peaks form (tips curl). Gradually add sugar, about 1 tablespoon at a time, beating until stiff peaks form (tips stand straight). Gently fold in 1/2 cup of the coconut and the chocolate.
Drop mixture into a total of 18 mounds on the prepared cookie sheets, using 2 tablespoons of the egg white mixture for each mound and leaving about 1 inch between mounds. Sprinkle with the remaining 1/4 cup coconut. Place cookie sheets on separate oven racks. Bake for 15 minutes.
Rotate cookie sheets in oven by moving the top cookie sheet to the bottom rack and moving the bottom cookie sheet to the top rack. Turn off oven; let macaroons dry in oven for 25 minutes. Transfer to a wire rack; cool. Store between sheets of waxed paper in an airtight container in the refrigerator for up to 2 days or freeze for up to 3 months.