Preheat oven to 250 degrees and line a baking tray with parchment paper.
In a very clean stand mixer bowl, whisk the egg whites until frothy. Start to sprinkle in the 1 cup sugar gradually until the meringue is at the stiff peak level.
Add the vinegar and cornstarch and whisk
Transfer the meringue to your baking tray and spread it out with a spatula roughly until about 12 inches by 8 and an even thickness.
Place in the oven and bake for 1 hour and 15 minutes. Turn the oven off and leave the door open slightly to let it cool. You can do this overnight but the meringue must be allowed to cool completely.
Once the meringue is cool, clean the mixer bowl and then beat the cream and sugar until soft peaks have formed.
Spread the cream on top of the meringue spreading it out to almost the edge.
Slice one banana and lay the pieces all over the cream then add the crushed cookies.
Top with more sliced banana and then drizzle the caramel sauce all over the pavlova.
Finally garnish with chopped chocolate and serve at once.P
Basic Pavlova recipe from The Joy of Baking.