Peel the mango and cut the flesh away from the stone. Zest and juice the lime. Peel and chop the banana.
Put all the chopped veg in a blender with the cashews and 250ml ice cold water. Blitz to make a smooth drinking, adding a little more water if you think it needs it. Serve straight away.
Mango a little firm when you unpack your box? Pop it in a paper bag with the banana. It should ripen up in a couple of days.