white wine vinegar
Step by step
Put the egg whites in a bowl.
Put the KitchenAid Cordless Hand Mixer to speed 7 and whisk the egg whites until they form stiff peaks.
Continue whisking and start adding the caster sugar one tablespoon at a time. Whisk until the meringue is stiff and looks glossy.
Add white wine vinegar and cornstarch and whisk shortly untill combined.
Scoop out the meringue and drop into mounds on a parchment paper-lined baking sheet.
Bake for 2 hours in a 100°C oven. When completely baked, let cool in the oven.