In a saucepan, combine heavy cream and sugar over medium heat until sugar dissolves. Do not boil.

In a small bowl, sprinkle gelatin over cold water and let it sit for 5 minutes to bloom.

Once the cream mixture is warm, remove from heat and stir in the bloomed gelatin and vanilla extract until fully dissolved.

Pour the mixture into ramekins and refrigerate for at least 4 hours until set.

In a saucepan, combine rhubarb, sugar, water, and lemon juice. Bring to a boil over medium heat.

Reduce heat and simmer for about 10 minutes until rhubarb is tender and the mixture thickens slightly.

Remove from heat and let cool. Strain if desired for a smoother texture.

Once the panna cotta is set, top with rhubarb compote before serving.