Preheat oven to 275°F (135°C). Line two baking sheets with parchment paper.
Beat egg whites in large glass or metal mixing bowl with electric mixer until frothy. Add cream of tartar; beat until soft peaks form. Gradually beat in sugar, 1 tbsp (15 mL) at a time, until sugar is dissolved and stiff, glossy peaks form. Fold in vanilla.
To make meringues, dollop about 2 tbsp (30 mL) mixture per meringue onto baking sheet. Alternatively, pipe mixture onto sheets using a piping bag with a star tip or a re-sealable bag with the corner snipped.
Bake in preheated 275°F (135°C) oven until firm, about 55 to 60 minutes. Cool completely and store meringues in airtight container. Makes about 48 meringues.