Chill Your Stemware: Place a martini or coupe glass into the freezer for 5 minutes to frost.
Fill the Shaker: Add the non-alcoholic spirit, passion fruit puree, pineapple juice, vanilla syrup, and fresh lime juice into a cocktail shaker filled with ice.
Shake Vigorously: Seal the lid and shake hard for 15 to 20 seconds. Shaking forcefully is crucial here to build up a nice, velvety froth on the surface of the liquid.
Double Strain: Pour the mixture through a fine-mesh strainer into your chilled glass to catch any small ice chips or fruit pulp.
The Final Presentation: Gently float half of a fresh passion fruit right on top of the frothy foam layer. Pour 2 ounces of chilled, non-alcoholic sparkling wine into a separate shot glass to serve as a sidecar.