Grease baking tray. Prefer if you line tray with greaseproof paper. Draw an 15cm/8 inch circle on the paper.
In a small cup or bowl, stir together the sugar, cornflour and cream of tartar. In a large glass or metal bowl, whip the egg whites with salt, vanilla and vinegar until soft peaks form. Gradually sprinkle in the sugar mixture and continue to whip until stiff and shiny. Mound the mixture into the traced circle on the baking sheet. Flatten the top and smooth the sides using a metal spatula.
Place in the preheated oven, and immediately reduce the heat to 150 degrees C. Bake for 1 to 1 1/2 hours, until a pale golden brown. Turn off the oven, and leave the lid/door slightly open with the pavlova inside until completely cooled.
Just before serving time, invert the cooled pavlova onto a serving plate, and top with slices of banana. Cover banana with caramel sauce. Top that with whipped cream and sprinkle with grated chocolate.