Preheat the oven to 140°C (285°F) fan-forced. Arrange four 130 ml (4 ½ fl oz) ramekins in a baking dish.
Heat the cream with the vanilla bean in a saucepan until it simmers. Remove from the heat, cover, and let it stand for 10 minutes to infuse the vanilla. Remove the pod and scrape the seeds back into the cream.
Mix the egg yolks with the caster sugar in a bowl until just combined. Gradually add the hot cream to the egg yolks, a ladleful at a time, while stirring continuously to temper the yolks. Avoid whisking too much to prevent incorporating excess air bubbles.
Pour the cream mixture into the ramekins. Fill the baking dish with boiling water until it reaches two-thirds up the sides of the ramekins. Bake for 40 minutes, or until the custards have a uniform jiggle in the centre. Let the custards cool, then cover and chill in the refrigerator for at least 4 hours or overnight.
In a small pan, place sugar and pour a splash of water on the edge. Heat on high without stirring until amber to mahogany. Pour it onto a lined tray to cool completely, then crush in a food processor into fine caramel powder.
Before serving, sprinkle the powder on your crème brûlée and gently torch until golden crispy.
