Preheat the oven to 275F (140C) and place the rack in the middle of the oven. Line a baking tray with foil and set aside.
Beat the egg whites with a clean electric mixer in a clean metal bowl until soft peaks form.
Gently sprinkle the sugar into the egg whites, one teaspoon at a time. Do not pour the whole amount in at once and don't stop beating the eggs until all the sugar has been incorporated to form glossy stiff peaks.
Sprinkle the tapioca starch and vinegar on the egg white mixture and fold in gently with a plastic spatula. Add the vanilla and gently fold the mixture again.
Gently spread the meringue in the desired shape on the foil-lined baking tray and ensure the edges are slightly higher than the center.
Bake for 1 hr 15 mins or until it goes a very pale, pinkish egg shell color.
Turn the oven off and leave the door slightly ajar to let the meringue cool completely. Some cracking is normal during this stage.
Remove from the oven and carefully remove from the foil. Decorate with whipped (dairy-free) cream and fruit as desired.