Panna Cotta is a custard set with gelatin. In Italian, Panna Cotta just means “cooked cream.”
In a small bowl, sprinkle gelatin powder over cold water. Let stand for 3 to 4 minutes until absorbed. Set aside.
Meanwhile, in a small saucepan combine both creams, sugar, salt, vanilla bean scrapings and coconut over medium heat. Warm gently until just steaming, but not boiling. Turn heat off. Cover and let stand for 5 minutes to steep coconut. Strain and discard coconut. Stir in gelatin.
Whisk in the sour cream until smooth. Pour into 4 well-oiled ramekins and chill for at least 3 to 4 hours until set. Unmould onto a plate. Serve with coconut shards.