Heat the oven to 325F degrees.

Beat the aquafaba and cream of tartar on high with an electric mixer. Do not use too deep a bowl; the beater must be able to adequately whip the liquid to make it stiff.

When the aquafaba is frothy, gradually add the sugar and continue to beat on high until stiff peaks form. This takes much longer than whipping egg whites, perhaps 15-20 minutes.

Add the salt and vanilla. Mix.

Add the coconut and mix.

Drop by small teaspoonsful (so the cookie is about 1" in size) onto a cookie sheet covered in brown paper (like a shopping bag). Each cookie will expand to about 2".

Bake for about 15-18 minutes until the cookies are puffed up and delicately browned.

Remove from oven, slip the brown paper off the pan. Put a wet towel on the pan. Return the brown paper with cookies to the pan (on top of the wet towel). Let this sit for about a minute to steam the cookies for easy removal.

Remove cookies carefully using a spatula or your fingers. Cool thoroughly and store in an air-tight container.