- Pour water into small bowl; sprinkle gelatin over. Let stand until gelatin blooms, about 10 minutes.
- Heat cream, lemon peel, and sugar in medium saucepan over medium-high heat, stirring constantly until sugar dissolves. Increase heat and bring to a low boil, stirring occasionally. Strain out lemon peel if you like, or keep it in if you prefer and slice it thinly. Remove cream mixture from the heat and add it a cup at a time to the hydrated gelatin, stirring until gelatin dissolves. Stir in buttermilk, and divide mixture into individual serving dishes or a pie tin. Refrigerate panna cotta until set, at least 4 hours but preferably overnight. Cover and chill. (The panna cotta can be made 2 days ahead)
- Using small sharp knife, cut around panna cotta. Place plate atop each ramekin and invert, allowing panna cotta to settle onto plate. Top with berries and serve chilled.