In a medium mixing bowl allow egg whites to stand at room temperature for 30 minutes. Meanwhile, grease a cookie sheet; set aside.
Add vanilla, cream of tartar, and food coloring to the egg whites. Beat with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add sugar, 1 tablespoon at a time, beating about 5 minutes on high speed until stiff peaks form (tips stand straight).
Spoon meringue into pastry bag fitted with 1/2-inch round tip. Pipe small 1-inch-high mounds that end in an angled tip about 1 inch apart on prepared sheet.
Bake in a 300 degree F oven about 15 minutes or until edges are very lightly browned. Transfer cookies to a wire rack; cool.
When cookies are cool, dip bottoms into melted chocolate, then into chopped walnuts. Set on parchment or waxed paper until chocolate is firm. If desired, add a dot of colored icing to each tip. Makes 48 cookies.