01 - Sprinkle powdered gelatin over cold water in a small bowl and let stand for 5 minutes until absorbed.
02 - Combine heavy cream, whole milk, and granulated sugar in a saucepan. Split the vanilla bean, scrape the seeds into the pan, and add the pod. If using vanilla extract, set aside to add later. Add a pinch of salt.
03 - Warm the mixture over medium heat, stirring continuously, until the sugar is dissolved and the liquid is steaming but not boiling. Remove from heat.
04 - Remove the vanilla pod and add the bloomed gelatin, stirring until fully dissolved. If using vanilla extract, stir it in at this stage.
05 - Distribute the mixture evenly among 4 ramekins or serving glasses. Allow to cool to room temperature, then refrigerate for at least 4 hours until fully set.
06 - Place mixed berries, granulated sugar, and lemon juice in a small saucepan. Cook over medium heat for 3 to 5 minutes, stirring gently, until berries soften and release their juices. Remove from heat and let cool.
07 - To serve, run a thin knife around the edge of each ramekin to unmold onto plates, or serve directly in glasses. Spoon berry compote over the top before serving.