Preheat the oven to 140C and place the rack in middle of the oven. Line a baking tray with paper and draw a large circle.
In a clean, medium-sized metal bowl, beat the egg whites with a clean electric mixer on medium speed. Beat until the whites form soft peaks.
While the beating, slowly sprinkle in the sugar then continue whisking until stiff peaks form – the mixture should be glossy.
Sprinkle the corn flour and vinegar on the meringue and fold in gently with a plastic spatula.
Now gently spread the meringue in the circle on the paper to fill in the drawn circle - Make sure the edges of the meringue are slightly higher than the center so you have a very slight well in the middle.
Bake the meringue for about 1 hour and 15 minutes or until it goes a very pale, pinkish egg shell color, then allow to cool completely.
Place the strawberries into a bowl and sprinkle on the castor sugar and the balsamic and toss gently – leave to steep for a few minutes.
Whisk together the cream, vanilla and icing sugar to soft peaks.
Assemble the pavlova by placing the meringue onto a plate, top with the whipped cream then top with the marinated strawberries.