Score the vanilla pod. Bring the cream, sugar, lemon zest, vanilla pod and pulp to the boil. Simmer for about 5 minutes while stirring. Pass through a sieve
Squeeze out the gelatine and dissolve in the hot cream while stirring. Pour into four small molds (100ml content) and refrigerate for 3 hours.
Puree the defrosted berries and powdered sugar, strain through a sieve. Remove the panna cotta from the edge with a squirting knife, hold it briefly in hot water. Topple the panna cotta.