Preheat oven to 190°F. Line 2 baking sheets with parchment paper. Wipe down the bowl of your stand mixer with a little bit of distilled vinegar (this will ensure the bowl is very clean).
Add egg whites and cream of tartar to the cleaned bowl of your stand mixer fitted with the whisk attachment. Beat on low speed 15 seconds, then gradually increase speed to high.
Beat egg whites on high speed 4 to 6 minutes or until stiff peaks form. If you remove your whisk from the bowl and the mixture stand straight up, you've reached stiff peaks.
Add vanilla and 1 drop of food coloring (optional) to the bowl and whisk on high just until combined. Transfer meringue to a piping bag fitted with desired piping tip.
Use the piping bag to dab a very small amount of meringue underneath each corner of the parchment paper (to help the paper stick to the pan).
Hold the piping bag perpendicular to the parchment paper, squeeze the bag, release pressure, and pull up to create dollops. You can also create hearts as I've done above (start with the left side of the heart and connect with the right).
These cookies will not spread so pipe them as close as necessary.
Bake cookies 2 hours, turn off the oven without opening the oven door, and allow to cool in oven for another 2 hours. Store cookies in an airtight container 2 to 3 days.
