Preheat the oven to 200 degrees F and line a large baking sheet or two with parchment paper.
Add the aquafaba and cream of tartar to a large bowl.
Using a hand mixer or stand mixer with the whisk attachment, beat on high for 5 minutes, until soft peaks form.
Slowly add in the sugar, a few tablespoons at a time, and continue to beat until all the sugar is added. Add the vanilla as well and keep beating, until stiff peaks are formed, about 5 more minutes.
Spoon the mixture into a large piping bag and cut off the end. Pipe small circles of meringue to make the cookies, leaving an inch of space in between the cookies.
Place in the oven and bake for about 1 1/2- 2 hours. To check for doneness, take one out of the oven, let it cool for a minute, then gently open it to see if it's no longer gooey in the middle. If it's not gooey, it's done. If the middle is a bit gooey, keep baking. You want them to be fully crisp throughout.
Remove from oven and store in an airtight container for about 4-5 days. They are best the day of, but taste great for several days. Enjoy!