Set oven to 200°F. Separate egg whites one at a time into a small bowl then transfer each white to the bowl of your stand mixer, fitted with the whisk attachment. (Be very careful to not get any yolks into the bowl.)
Add cream of tartar and salt to the mixing bowl, then begin mixing on low. Gradually increase the speed to high
Once the egg whites have begun to froth up, begin to slowly sprinkle in the sugar a teaspoon at a time. (Taking your time is important here, so go very, very slowly.) After incorporating the sugar, whisk in the extract of your choosing. Beat until the meringue has a thick, marshmallowy texture, and holds a nice peak.
(Optional) Add a tiny amount of food coloring, and swirl around with a toothpick or skewer, or beat with the whisk attachment to distribute. Ensure your sugar is dissolved by rubbing a small amount between your fingers to determine if the meringue is smooth with no grit.
Transfer meringue to a piping bag that has been fitted with the large star attachment.
Add a small dollop of meringue to the corners of the baking sheet under the parchment paper to hold the paper down. Pipe small meringue kisses onto parchment paper, keeping about 1 inch of space between them.
Place on the center rack to bake at 200° for about an hour, then turn the oven off and keep it closed for an additional 2 hours. The kisses are done when they're dried throughout, and lift from the baking sheet easily, feeling light and dry.