Preheat oven to 250 degrees F(130 C).
Line two large baking sheets with parchment paper.
In a standing or electric mixer, beat whites until foamy. Add salt and cream of tartar and whip until soft peaks form. Gradually add sugar, beating at high speed until whites hold stiff, glossy peaks.
Spoon half of meringue into pastry bag and pipe cups, starting with a 2-inch diameter base, and coiling a rope around the base, twice.
Bake meringues for 1 hour, turning heat down to 225 degrees F (110 C) if they begin to brown.
Allow meringues to cool in oven with heat off and door slightly ajar.
Store cooled meringues in an airtight tin.