Preheat oven to 300°F/150°C to start. We will lower this temperature when baking.
Place a layer of baking paper on a baking tray. Using a pencil and a dinner plate as a guide (around 10"/25cm), make circle. Make a second smaller circle inside (around 6"/15cm) resembling the shape of a round wreath.
Using an electric mixer, beat the egg whites until soft peaks form.
Slowly add one tablespoon of sugar at a time, while beating the mixture until it's thick and glossy. Add cornstarch and vinegar and beat until mixed throughout.
Using a tablespoon, scoop the meringue within the traced lines on the baking sheet, forming a wreath shape.
Using the back of your spoon, gently smooth out the top of the meringue, where your cream will sit. On the visible sides of the meringue, create a small wave, or peak of meringue, which looks nice when it's baked.
Reduce oven to 225°F/110°C (traditional oven) or 210°F/100°C (fan forced oven), and place the pavlova wreath in the oven. Bake for 1.5 hours, or until the pavlova is ivory, not brown.
Turn off the oven, and allow the pavlova to cool completely in the oven. If you remove the pavlova before it's completely cool, it will crack.