1. In a small bowl, sprinkle gelatin over cold water and let it sit for 5 minutes.
2. In a saucepan, heat the heavy cream and sugar over medium heat until the sugar dissolves. Do not boil.
3. Remove from heat and stir in the vanilla extract and gelatin mixture until completely dissolved.
4. Pour the mixture into serving glasses and refrigerate for at least 4 hours or until set.
5. For the berry compote, combine berries, sugar, and lemon juice in a saucepan. Cook over medium heat until the berries break down and the mixture thickens, about 10 minutes. Let it cool.
6. Once the panna cotta is set, top with the berry compote and serve.