Preheat oven to 200oC. Draw a 24cm (diameter) circle on a sheet of baking paper. Repeat on another two sheets of baking paper. Place, pencil-side down, on a baking tray. Dust each tray lightly with 1 teaspoon cornflour.
Using an electric mixer, beat 6 egg-whites and 1 tsp of cream of tartar in a large bowl until soft peaks form. Add 1 and 1/3 cups of sugar, 1 tablespoon at a time, beating constantly until thick and glossy. Add 3 teaspoons cornflour with the last tablespoon of sugar. Fold through 1 tsp vinegar. Spoon meringue onto baking paper. Shape into a circle, using the pencil mark as a guide.
Repeat steps 2 two times to result in three meringues.
Reduce oven to 100oC. Bake for 1 1/4 to 1 1/2 hours or until dry and crisp. Turn off oven and open oven door. Cool completely in oven (pavlovas may sink during cooling).
Place one meringue on a serving dish and top with 1/3 of the cream. Arrange sliced strawberries over cream. Top with another meringue, followed by 1/3 cream and strawberries. Finally, top with the last meringue, remaining cream and then scatter strawberries and raspberries over the top.