In a small bowl, sprinkle gelatin on cold water. Set aside for 10 minutes to allow the gelatin to dissolve. Meanwhile, in a medium bowl, whisk together 1/2 cup of the cream, the sour cream and vanilla, set aside. In a small saucepan, heat the remaining 1/2 cup of cream and the 1/3 cup of sugar over medium heat until simmering. Remove from heat once mixture simmers. Off the heat, add the softened gelatin to the hot cream and whisk to dissolve. Strain hot cream/sugar/gelatin mixture into the cold cream/yogurt/vanilla mixture and stir to combine. Pour into glasses. Refrigerate for 4-8 hours until firm. Serve with berry syrup and fresh berries.

Combine half of the berries, sugar, lemon zest and lemon juice. Bring to a boil over medium heat, continue boiling for 5 minutes, crushing a few berries while stirring consistently. Remove from heat, add vanilla, stir well. Cool to warm. Fold in remaining berries. Spoon on top of panna cotta before serving.