Preheat the oven to 275°F (135°C).
Draw an 8-inch circle on a piece of parchment paper.
Flip the parchment paper so the pencil side doesn’t touch the meringue, and place it on a baking sheet.
For the meringue, mix the cornstarch into the white vinegar (you should get a smooth white liquid).
Beat the egg whites with a mixer until they become foamy.
Very gradually add the granulated sugar (2 to 3 tablespoons at a time) while continuing to mix.
Keep mixing until you obtain a glossy white mixture.
Tip: You should see stiff peaks when you lift the whisk. Also, to test consistency, rub a bit of meringue between your fingers. If you don’t feel sugar granules, it’s ready.
Spread the meringue inside the 8-inch circle on the parchment paper.
Tip: To keep the parchment paper from sliding, use a small dab of meringue under each corner to stick it to the baking sheet.
Bake for one hour.
After one hour, open the oven door slightly for 20 minutes.
After 20 minutes, remove the meringue and let it cool completely. It will crack and sink a little.