Mix the juice, coconut milk and vanilla (you can also use 3 sachets of vanilla sugar) with the preserving sugar and let stand for 20 minutes.
Bring to the boil and simmer for 3 minutes, remove from the stove and pour in the sparkling wine. When the whole thing boils again, let it cook for another 2 minutes.
Remove from heat again and mix in the vodka and citric acid, pour into glasses immediately and close.