Cut and peel your banana and mango (discard the stone). Put in a blender. Halve the passion fruit. Set a sieve over a bowl. Squeeze the passion fruit into the sieve and squeeze the seeds to extract as much juice as possible. Pour the juice in with your mango and banana. Whizz till smooth.
TIP: Mango not ripe? Pop it in a bag with the banana and it should ripen in a couple of days.