Put water in a small bowl and sprinkle with gelatin. Set aside for 15 minutes until softened.
In a large bowl, whisk 1 cup whipping cream and yogurt together. Set aside.
Over medium heat, put remaining cream and 1/2 cup sugar in a small sauce pan. Split vanilla bean and scrape out seeds with a spoon. Add the seeds and the bean to the pan. Stir until sugar is dissolved and cream begins to simmer. Remove from heat and remove vanilla bean.
Add the gelatin to the hot cream pan mixture and stir to dissolve the gelatin into the cream. Add hot cream and gelatin mixture to bowl of cream and yogurt, and stir to combine. Divide mixture into individual serving cups, cover with plastic wrap and refrigerate at least 3 hours or overnight.
minutes before serving, gently toss strawberries, vinegar, 1 T sugar and fresh ground pepper to combine. Spoon over panna cotta when ready to serve.