Mango passion fruit roulade

INGREDIENTS

• 3 large egg whites
• 175g caster sugar
• 1 level tsp cornflour
• 1 tsp malt vinegar
• 1 tsp vanilla extract
• icing sugar , to dust
• 200g fat-free Greek yogurt
• 1 large ripe mango , peeled, stoned and diced
• 4 passion fruits , pulp only
• icing sugar (optional) and a few physalis, to decorate
• raspberry sauce , to serve (see 'Try' below)