Place egg whites, cream of tartar and salt in the bowl of a stand mixer
2 egg whites, ¼ teaspoon cream of tartar, pinch salt
Using the whisk attachment, whisk at medium speed until the egg whites become very frothy, about 2-3 minutes
Increase the speed to medium high and slow add the sugar, 1 tablespoon at a time
Increase the speed to high and beat until the egg whites are glossy and form stiff peaks, about 3-4 minutes
Turn speed to low and add the peppermint extract. Mix for just until extract is mixed in
¼ teaspoon peppermint extract
Use a cake decorating disposable bag and fit with a large tip. I used a 1M tip.
Using a long wooden skewer, dip just slightly into the red gel food coloring. Line the inside of the decorating bag with two lines of the red coloring
Fill decorating bag with meringue
Pipe meringues onto the prepared baking sheets, leaving about 1 inch between each meringue
Bake both trays of meringues in preheated oven for 1 hour. Turn the oven off and leave the meringues in the oven for 30 minutes.
Test the meringues. If the centers are still chewy, return to the warm oven for additional time.
Notes
Make certain your mixing bowl is dry and does not contain any greasy residue
When separating eggs, be certain not to get any yolk into the whites. Any bit of yolk will prevent the whites from forming the glossy peaks.
Whip until the meringue is glossy, and forms stiff peaks. Stop the mixer to check partway through. If the meringue flops over and doesn't hold its shape, keep mixing.
You don't want to undermix meringues, but you also don't want to overmix them either.
It doesn't take much food coloring to add color to the meringues.
To pipe the kiss shaped meringues, hold the piping bag straight up and down with the tip just slightly above the surface of the tray. Squeeze the bag until the meringue is about one inch. Stop squeezing and lift bag straight up.
The color of the meringues will change color as the meringue flows through the bag. The first few meringues may be entirely white until they begin to pick up the color.
Store peppermint cookies away from other cookies. The peppermint scent will permeated any nearby cookies if stored together.