1. Lightly oil 6 x 180ml-capacity moulds or small teacups. Place milk, sugar and 2 cups of measured cream in a saucepan. With the tip of a sharp knife, scrape out the seeds of the vanilla bean. Add the bean and the seeds to the pan and bring just to the boil, stirring until sugar dissolves.
2. Set aside for flavours to infuse for 15 minutes, then strain mixture to remove vanilla bean. Dissolve gelatine powder in ¼ cup water in a small ramekin, then heat ramekin in a microwave or double boiler until the gelatine is liquid. Whisk gelatine into hot cream mixture until incorporated. Set mixture aside to cool.
3. Lightly whip remaining cream and fold into cooled mixture. Pour mixture into prepared moulds. Refrigerate for at least 4 hours or preferably overnight to set.
4. To serve, dip moulds in boiling water for a few seconds, then invert on to plates and shake to turn out.

Tip: Panna cotta literally translates as "cooked cream". For best results, after un-moulding, leave panna cottas to come to room temperature before serving, as this removes the fridge-cold solid consistency and makes them soft and creamy to eat.