I enjoy a cocktail from time to time, especially a Mojito but this one comes a close second.
Just to clear up any misunderstanding. Passion fruit = Americas, passionfruit = UK and the Commonwealth, and purple granadilla = South Africa. It is native to Brazil, Paraguay and northern Argentina.
In the event that you cannot find Passionfruit then use Sharon fruit (Persimon) instead.
2 parts vodka
3 splashes lemon Juice
1 half passionfruit
1 teaspoon brown sugar
Muddle passionfruit and brown sugar in a shaker. Fill with crushed ice. Add lemon juice and vodka. Shake and strain into glass filled with crushed ice.
By the way the flower of the Passionfruit is the national flower of Paraguay.
Health note: Passionfruit juice is a good source of potassium, possibly making the fruit relevant as a nutrient source for lowering risk of high blood pressure although adding vodka probably negates this.