Preheat the oven to 200°C and grease 6 x 300 ml ramekins with nonstick spray. Sprinkle a little caster sugar into each ramekin, shaking and tilting it to coat the bottom and sides with the sugar. Tap the ramekins to loosen any excess sugar and then remove it.
Whisk together the egg yolks and sugar in a metal bowl until the mixture is thick and pale yellow. Place the bowl over a saucepan of simmering water and stir over low heat until the mixture is thick and heated through.
Remove from the heat and place over a bowl of ice-cold water. Stir until the mixture has cooled.
Fold in the granadilla pulp. Beat the egg whites in a clean bowl until soft peaks form. Add the cornflour and beat for 1 minute. Fold half the egg whites into the granadilla mixture until lightly but well-mixed. Fold in the rest of the egg whites.
Spoon the mixture into the prepared ramekins, filling them to 1 cm from the top. Bake for 5 minutes, reduce the oven temperature to 180°C and bake for another 12 minutes or until the soufflés are golden brown on top.
Dust with icing sugar and serve immediately.