Put the passionfruit puree, pisco, Simple Syrup and cilantro into a cocktail shaker. Muddle the cilantro, add large ice cubes and shake. Double-strain into a champagne flute and fill with Moscato d'Asti. Stir gently will a bar spoon, garnish with a slice of lime and serve.
Combine the sugar and 1 cup water in a small saucepan and bring to a boil. Cook, stirring, until the sugar dissolves. Remove from the heat and let cool completely. Keep covered in the refrigerator up to 1 month.