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).
Heat a large pan over a medium heat. Add the coconut and toss in the pan for 1 to 2 minutes until lightly toasted.
Serve the sorbet in champagne coupes and eat straight away with a sprinkle of the toasted coconut and mint leaves.