Divide the melon in half and remove the inner seeds.
Cut the two halves into melon balls using a melon ball scoop. Place in a large bowl and set aside.
Remove the watermelon skin and cut it into regular cubes, which you will then add to the melon in the bowl.
Slice the tropea onion and rinse the olives and capers with stalks. Add these into the bowl and season with a drizzle of oil, pepper, a pinch of salt and the hand-minced basil.
Cut the feta into cubes and combine with the remaining ingredients.
Stuff a hollowed-out melon with the watermelon and feta salad, and add the slices of Prosciutto di San Daniele last.