Preheat the oven to 200°F. Line a baking sheet with parchment., In a large bowl or the bowl of your stand mixer, combine the egg whites, cream of tartar, and a dash of salt. Beat until peaks form, then gradually add the sugar, continuing to beat until the mixture is stiff and glossy., Pipe meringues onto the sheet, using a pastry bag and star tip; or drop meringues by large teaspoonfuls onto the sheet., Bake the meringues for 1 1/2 hours. Turn the oven off with the meringues still inside and the door shut; leave them there until they're completely cool, about 3 hours or more., Store the meringues in an airtight container at room temperature for up to two weeks.