CUT the vanilla bean in half and scrape contents onto knife.
ADD to cream and sugar and simmer over low heat for ½ hour.
In the meantime, SOAK the gelatin in cold water, then ADD it the cream and STIR fast with a whisk to avoid lumps.
When the cream is almost cold, STIR in the sour cream.
POUR the mixture into the molds or glasses and refrigerate overnight.
Frutti di Bosco:
MARINATE the berries with all ingredients 1 hour before serving.
Notes
Variation:In winter for a warm sauce, heat a non-stick pan with a tablespoon of butter.When gold in color, ADD all the ingredients and quickly toss for a couple of minutes.SERVE warm next to the panna cotta.