Preheat oven to 220″C. position oven shelf near the bottom of the oven.
Draw three 7 inch circles onto a sheet of baking paper and place face down onto a baking tray.
Using a large mixing bowl, Beat egg whites and cream of tarter on a medium speed until light and foamy.
Add cornflour and vinegar and continue to beat until soft peaks form. Gradually add sugar, 1 tbsp at a time, while beating on high speed until thick and glossy
Fold through rosewater. Spoon mixture onto paper to cover circles Using a palette knife, smooth side and top.
Place into oven and reduce heat to 120 “C. Cook for 1 hour 15 minutes.
Turn off oven and prop open oven door with a towel or wooden spoon.Allow the pavlova to cool down slowly for 4 to 5 hours or overnight preferably.
Arrange melon on a wire rack in a single layer, sprinkle with 1 tablespoon rosewater and 2 tablespoons sugar, then stand for 30 minutes for flavours to infuse.
Meanwhile, combine berries and another 1 tablespoon rosewater in a bowl, then stand for 15 minutes to infuse
Whisk the cream. Add the remaining 1 tablespoon rosewater and whisk until soft peaks.
Place one pavlova disc on a serving plate and sprinkle with a little extra rosewater. Spread over one-third of the cream, top with half the watermelon. Repeat layers, then top with a final layer of disc and cream. Arrange lychees, watermelon balls and strawberries into the cream, then garnish with pistachios and dried rose petals.
Note - I have used double cream so skipped the sugar altogether. Now if you are using thickened cream,Whisk the cream with 2 tablespoons of sugar with electric beaters until thickened. Add 1 tablespoon of rosewater and whisk until soft peaks.