Place watermelon onto a damp cloth on a chopping board. Using a large sharp knife, carefully cut a 12cm-wide slice from the watermelon, then cut a 10cm-wide slice and an 8cm-wide slice.
Place the 12cm watermelon round onto the board. Using a small sharp knife, remove the rind and and white flesh. Shape the melon flesh with a small sharp knife to form a round shape. Place the watermelon round onto a large heavy-duty serving plate.
Remove rind and white flesh from the remaining watermelon slices and trim to form rounds. Place watermelon slices onto the watermelon base to form a layered cake shape.
Using a 3cm star-cutter, cut pineapple flesh into stars. Thread a pineapple star and 3 blueberries then another pineapple star onto an 18cm bamboo skewer. Repeat to make 10 skewers. Insert skewers into the top of the watermelon cake.
Using a 4cm star cutter, cut stars from the rockmelon. Use a melon scoop, to scoop balls from the watermelon
Decorate the watermelon cake with remaining blueberries, rockmelon stars and watermelon balls (see the photo). Serve with any remaining watermelon balls.
Tips & Hints:
Choose a watermelon that feels heavy for its size and has a hollow sound when tapped.
Note, this fresh fruit cake can be made a few hours ahead of serving and
stored in the fridge.