Remove the pulp from the passion fruits and blitz in a food processor to help remove the pulp from the seeds. Pass the pulp through a sieve to extract the seeds. Add a tbsp of the seeds back into the juice and discard the rest of the seeds.
Place the sugar and water in a small saucepan and bring to the boil, stirring continuously until the sugar has dissolved. Leave to simmer until it creates a syrup liquid. Remove from the heat and add to the passion fruit juice, along with the glucose syrup. Stir well and leave to cool. Refrigerate for a minimum of 2 hours, preferably overnight.
Attach the gelato paddle and slowly pour the passion fruit mix into the ice cream/gelato bowl. Close the lid and set the timer for 40 minutes. Churn until the sorbet reaches the desired consistency. Decant to an airtight container and keep in the freezer until required.
For the cocktails, spoon a teaspoon of sorbet into the bottom of a champagne flute and top with Prosecco. Stir and serve immediately.