In a medium bowl, beat together the cream, milk, caster sugar and vanilla seeds until well mixed. Stir in the egg yolks, mix well and chill in the fridge overnight.
The next day, preheat the oven to 170 C / Gas 3.
Give the chilled mixture a stir and spoon into six ovenproof ramekins. Place the small dishes into a roasting tray and pour boiling water into the tray to a depth of half way up the side of the ramekin dishes.
Bake in the preheated oven for 40 to 45 minutes until the custard sets and is firm. Remove the ramekins from the oven and then from the roasting tray and let cool.
Before serving, sprinkle with brown sugar. Using a crème brûlée torch or by placing the dishes under the grill, caramelise the sugar until golden brown.
To get that perfect golden brown crisp layer of caramel, try playing around with different types of sugars. Low-moisture, superfine sugars like caster sugar work well.