The instant in the title is no exaggeration. This sorbet can be made with minimum effort and serious results. Serve it as a light and refreshing dessert.
Peel the mangoes and cut the flesh into chunks. Cut the banana into chunks and spread out on a tray. Place in the freezer for at least 4 hours or overnight if possible.
Place the frozen mango and banana into a food processor with the lime zest and juice. Blitz on high until the mixture is the consistency of a thick sorbet (you can add a couple of tablespoons of ice-cold water if the consistency looks too thick).
Transfer to individual serving glasses and eat straight away.