This unusual combination will satisfy any gourmet, only the mango must be unripe. If you wish, you can use a papaya instead of the mango.
Soak the mango briefly in cold water to remove any syrup. Meanwhile, stir through the juice of one lemon, chili, shallots and soy sauce. Drain the water in which the mango is soaking. Mix the mango with the water chestnuts.
For the melon basket, cut the watermelon a tiny bit flat at the bottom to make it stand up better. Place a kitchen knife horizontally in the center and rotate the melon on its axis so that the kitchen knife draws a straight line around the center of the melon. At right angles to this line, use the kitchen knife to draw two lines for a 2, 5 cm wide handle that runs across the highest point and meets the horizontal center line repeatedly at the other end.
(If you want, you can mark a zigzag basket edge now, before making deep cuts). Using a sharp kitchen knife, make a deep vertical cut along the marking lines for the basket handle. Then score the other side of the handle. Then follow the center line and cut a straight or zigzag line. Always make sure that the kitchen knife is pointing to the center of the melon and is parallel to the surface. This is the only way to be sure that when it hits the handle cut, the cut piece of melon can be pulled out cleanly.
The fruit pulp