Peel the grapefruit and cut the segments off the sheets.
Peel the prawns, remove the intestinal tract and cook or fry briefly. Cut in half lengthwise and let cool.
Mix the mint, coconut milk, oyster sauce, fish sauce, lime juice, chili pepper and ground pepper in a small bowl. Mix this with the grapefruit, shallot and prawns. Place on a plate. Sprinkle the peanuts on top and decorate with a handful of fresh herbs.