For tips on working with egg whites, see Beating Eggs. To make chocolate meringue kisses, whisk ¼ cup unsweetened cocoa powder into the sugar.
Preheat the oven to 225°F. Line 2 baking sheets or cookie sheets with parchment paper.
Prepare:
If desired, fold in:
Using a pastry bag fitted with a ½-inch open star tip or a zip-top bag with a bottom corner snipped off, pipe the batter into 1 ¼-inch kisses about 1 inch apart on the baking sheets. (Or, drop heaping teaspoons of batter in peaked mounds.) Bake for 45 minutes, switching oven racks and rotating the sheets halfway through. Turn the heat off and let the cookies stand in the oven for 30 minutes, or until cool.