Bloom the gelatin: Sprinkle gelatin over cold water in a small bowl. Let it sit for 5-10 minutes until it becomes spongy.

Heat the cream mixture: In a saucepan, combine heavy cream, milk, and sugar. Split the vanilla bean and scrape seeds into the mixture (or add vanilla extract). Heat over medium heat until steaming but not boiling, stirring occasionally.

Dissolve gelatin: Remove the cream mixture from heat. Add the bloomed gelatin and stir until completely dissolved.

Strain and pour: Strain the mixture through a fine-mesh sieve into a jug. Pour into ramekins or glasses. Let cool slightly, then refrigerate for at least 4 hours or until set.

Make berry coulis: Blend berries and powdered sugar until smooth. Strain to remove seeds if desired.

Serve: To unmold, dip ramekins in hot water for a few seconds, then invert onto plates. Alternatively, serve in glasses topped with berry coulis.