Put the orange juice in a small microwave-safe bowl, sprinkle over the gelatine, stir and set aside for 5 minutes until the powder absorbs the juice. Microwave on high (100%) for 20 seconds, or until the powder dissolves and then stir and then set aside to cool slightly.
Meanwhile cut the cheeks off the mangoes and any other flesh for the seed.
Set aside one cheek to use later for decorating. Remove the skin (scoop the flesh out with a spoon is and easy way) and roughly chop the remaining flesh and put into a small food processor and process until pureed.
In a large bowl, whisk together the mango puree and yoghurt until smooth, add the gelatine mixture and whisk until well combined and smooth.
Evenly pour into four glasses and place on a tray and place in the fridge for 6 hours or until set.
Scoop flesh from reserved mango cheek and thinly slie and then evenly arrange on top of mousses and spoon over the passionfruit pulp.