How to Make It
Preheat the oven to 200°. Line 4 large baking sheets with parchment paper or foil. Bring a large skillet of water to a simmer over moderately high heat. Place the egg whites in a large stainless-steel or glass bowl and swirl over the hot water to warm the whites. Add 1 cup of the sugar and the cream of tartar. Beat with an electric mixer at medium speed for 30 seconds. Increase the speed to high and beat until the meringue is thick and glossy and holds a peak, 3 to 5 minutes. Beat in the vanilla and salt.
Fit a large pastry bag with a 1/2-inch plain tip and scoop the meringue into the bag. Pipe the meringue into tight, 3-inch long "S" shapes. Bake the meringues for 1 1/2 to 2 hours, or until they are firm to the touch and lift easily off the pan. Let cool on baking sheets.
Have ready a bowl of ice water, a folded towel and a soup spoon. In a small heavy saucepan, combine the remaining 1 cup of sugar with 1/4 cup of water. Cook over high heat, stirring, until the sugar dissolves. When the mixture boils, stop stirring and cook undisturbed until a gold-amber caramel forms. Set the bottom of the pan in the ice water for 30 to 60 seconds; stir the caramel as it cools.
When the caramel falls off the spoon in a thin, steady stream, lift the pan from the water and dry the bottom with the towel so that no water falls on the meringues. Hold the spoon high and drizzle the caramel over the meringues in abstract patterns; keep the spoon moving so you get pretty lines rather than blobs. Let the caramel set for 1 minute.