Stiffened, sweetened egg whites can be used for simple cookies such as these kisses.
Heat oven to 200 degrees. Line 2 baking sheets with parchment paper; set aside.
In the heatproof bowl of an electric mixer, combine the egg whites, sugar, and cream of tartar. Place the bowl over a pan of simmering water. Whisk mixture constantly until the sugar has dissolved and the whites are warm to the touch, about 3 minutes.
Transfer bowl to mixer fitted with the whisk attachment. Starting on low speed and gradually increasing to high, whip until stiff, glossy peaks form, about 10 minutes. Add the vanilla and food coloring, and mix until combined.
Transfer the meringue to a 14-inch pastry bag fitted with a large round tip (Ateco #7). On a lined baking sheet, pipe a kiss that is 1 1/2 inches in diameter; repeat, spacing kisses 1 inch apart.
Place baking sheets in oven, and bake until kisses have expanded slightly and they begin to crack, about 20 minutes. Reduce heat to 175 degrees, and bake until completely dry on the outside and slightly chewy on the inside, about 4 hours. Store in an airtight container in a cool, dry place up to 3 days.
The baking time will vary depending on your oven and the day's humidity. If the meringues start to brown, reduce the oven temperature immediately.