Heat oven to 350℉.
Line sheet pan with parchment paper.
Beat egg whites in stand mixer on medium-high speed until firm peaks form, 3-4 minutes.
With machine running, add super one spoonful at a time and beat until stiff and glossy, about 4 minutes more.
Using a spatula, fold in cornstarch and vinegar.
Use spatula to spread meringue onto parchment paper, creating whatever shape you desire. Use spatula to create spiky peaks on the meringue.
Place meringue in oven. Immediately turn heat down to 300℉. Bake 1 hour, until dry on the outside and chewy through the center.
Cool at room temperature at least 30 minutes. Meringue can be made earlier in the day for use later the same day.