Position two oven racks towards the center of the oven and preheat the oven to 200ºF. Set two large baking sheets with parchment paper aside.

To a large bowl using a hand mixer, or the bowl of a stand mixer fitted with a whisk attachment, add the egg whites, cream of tartar, and salt. Begin mixing on low speed gradually increasing to medium.

Once the egg whites start to become frothy, about 30 seconds, slowly add in the granulated sugar one teaspoon at a time. Once all the sugar has been incorporated, mix in the vanilla. Scrape down the bowl a few times while adding the sugar as it can build up around the edges.

Continue mixing on medium-high speed. The meringue is done once the sugar has fully dissolved and it has a thick marshmallowy texture that holds a nice peak, about 10 to 15 minutes. If adding food coloring, add a small amount using a toothpick and mix until fully incorporated.

Transfer the meringue into a large piping bag fitted with a large star tip. Pipe small dollops of meringue to the corners of the baking sheet and press the parchment paper down (this will act as a glue to keep your paper in place while piping).

To pipe the cookies, hold the piping bag about ½ inch above the paper, then squeeze to make about a 2-inches wide dollop. Then stop squeezing and lift the bag up to form the tip. Continue piping dollops leaving about an inch of space between them to allow airflow. (If you pipe 6 rows of 4, you will be able to fit 24 dollops on each sheet.)

Bake for about 1 hour or until they are dry to the touch and sound hollow when you tap on one. (If it is humid, they may take longer to bake.) Turn the heat off and leave meringue in the oven with the door closed for an additional 2 hours to dry out. They will be done when they feel light and can easily be lifted from the sheet.