Line 3 baking sheets with nonstick baking paper. Put the egg whites in a bowl and fork together until frothy but still clear. Add the sugar, oil and vanilla extract and mix together.
Sift the flour into the bowl and stir together. Spoon the mixture into 6 mounds on the baking sheets and spread each to a circle, about 12 cm (5 inches) across.
Place one of the baking sheets in a preheated oven, 190°C (375°F), Gas Mark 5, for about 5 minutes until the biscuits are light brown in the centre and slightly darker around the edges. Remove from the oven and leave to stand for 30 seconds. Put a second sheet in the oven, then repeat with the third.
Loosen the cooked biscuits. Working quickly, drape each biscuit over a large orange and pinch the edges to make a fluted edge. Leave to set for a few minutes then lift off the oranges, turn up the other way and put on to a wire rack. Repeat to make 6 cups.
Stand the mango on its side and cut a thick slice off each side. Cut the flesh away from the stone and peel and cut the flesh into slices. Mix with the berries. Spoon the yogurt, then the fruit into the cups. Transfer to serving plates, dust with icing sugar and serve immediately with passionfruit sauce (see below).