1Preheat oven to 150 degrees F (65 degrees C). Line a baking sheet with parchment paper. Trace around a 9 or 10 inch round pan onto the paper to make a guide for spreading the meringue.
2In a large glass or metal mixing bowl, beat egg whites until foamy. Gradually add sugar and salt. When mixture is stiff and sugar and salt appear to be dissolved, add the vinegar and vanilla.
3Spread mixture onto parchment paper, using the circular guide.