For the mayonnaise, place the egg yolk in a stick mixer bowl along with a dash of Worcestershire sauce, salt, a pinch of cayenne pepper, and a splash of lemon juice. Blend slowly. While continuing to blend, carefully pour in the vegetable oil until the mayonnaise reaches the desired consistency (you can also just blend by hand). Adjust the flavour once again with salt and a dash of rum.

Meanwhile, shell and devein the prawns, season them, and sear them in a pan.
Marinate the avocado, mango, papaya, and onion pieces in the olive oil with salt and lemon juice.
Arrange this colourful salad on plates, add two prawns per plate, drizzle on some pesto and balsamic vinegar, and do the same with a spoonful of the mayonnaise.