Preheat oven to 120°C/245°F or 110°FF
Line a baking tray with baking paper and draw a 23cm circle on the paper. Turn the paper over, with the circle facing down
In the bowl of an electric mixer, beat egg whites and cream of tartar on medium speed, until soft peaks form
Gradually add the caster sugar, 1 tablespoon at a time and continue beating for 30 seconds between additions. Once all the sugar has been added, keep mixing until meringue is smooth and glossy. All up, it will take around 10 minutes of mixing.
Take a small amount of meringue with your finger and wipe underneath the corners of the baking paper, sticking it to the baking tray.
Place mixture onto the tray, within the circle, then use an offset spatula to form the mixture into a high circle, creating furrows along the edges. Bake for 80-90 minutes, until shell is firm. If you need to check the crispness of the shell after this time, very quickly open the oven and tap the sides, closing the door immediately.
Once cooked, turn oven off and leave pavlova to completely cool inside the oven.