If using powdered gelatine (gelatin), sprinkle the gelatine over the milk and allow to stand for 5 minutes. If using gelatine leaves, soak the gelatine leaves in cold water for 5 minutes until softened then squeeze out any of the water before stirring it into the hot cream.
Heat the cream (and milk, if using gelatine leaves), sugar and vanilla in a small saucepan over medium heat until the sugar has dissolved and the cream is hot, but not boiling.
Stir the softened gelatine leaves into the mixture off of the heat until combined. If using powdered gelatine, stir the bloomed gelatine and milk into the cream and over low heat, stir until completely incorporated into the hot cream. Take care not to allow the mixture to boil.
Once the gelatine has been incorporated, allow the mixture to cool for 15 minutes, stirring regularly.
Pour into ramekins or small glasses then cover with plastic wrap and place in the refrigerator overnight (at least 6 hours).
Serve the panna cotta with fresh passion fruit and raspberries.