Try this for a summer treat! Do not worry if the roulade cracks a little. It's delicious. I'm not sure whether other countries have granadilla pulp in small tins, but otherwise use fresh pulp. You could also use another fruit, but granadilla has such a wonderful flavour! Cream of tartar stabilises egg whites. NOTE: We call passion fruit "granadilla" or "grenadilla" but the Zaar format does not recognise that ingredient.