Make sure bowls and utensils touching egg whites are as clean and free of oils as possible.  Let eggs come to Room Temperature.  Separate eggs, making sure not yoke drops into the whites.  Using an electric mixer with a whisk attachment.  Beat the egg whites on medium speed until they form soft peaks.  Start adding the sugar slowly and continue to beat until all the sugar is dissolved and the meringue holds very stiff peaks.  Sprinkle the vinegar and cornstarch over the top of meringue and fold in with a rubber spatula.

Preheat the oven to 250 degrees and place rack in center of oven.  Line a baking sheet with the parchment paper.  Draw a 7 inch circle on the paper.  Gently spread the meringue inside the circle smoothing the edges.  Bake for 1 hour and 15 minutes or until the outside is dry and has a very pale cream color.  Turn the oven off and leave the door slightly ajar, letting the meringue completely cool in the oven.  (The cooled meringue can be stored in a cool dry place in an airtight container for a few days.)