Preheat the oven to 350° F.
Line 2 baking sheets with parchment paper. In a large bowl using an electric mixer, beat the egg whites and vanilla until foamy.
Add the cream of tartar and beat for about 1 minute more, being sure not to overbeat.
Add the sugar slowly. Continue beating and adding remaining sugar in batches, until all of the sugar is dissolved and the meringue is glossy.
Transfer mixture to a pastry bag or large zip-top bag fitted with large round tip. Pipe into 2-inch spirals on prepared baking sheet, leaving 1-inch of space between cookies. Place baking sheets in the preheated oven and turn the oven off. Leave the cookies undisturbed in the oven for at least 2 hours, or until cookies are crisp and dry.