Set 6 ramekins in a deep baking dish. Put 1 tablespoon of the macadamia nuts into each of the ramekins.
In a saucepan, stir the cream and sugar over medium heat. When the mixture comes to a slow simmer, add the white chocolate and remove from the heat. Whisk until the chocolate has completely melted. Stir in the egg yolks, one at a time, continuing to whisk until combined. Stir in the vanilla essence.
Divide the mixture evenly between the ramekins. Place the dish into the oven and then pour water into baking dish until ramekins are 3/4 submerged.
Bake in preheated oven until custard has set, about 45 minutes. Remove pan. Turn on grill.
Sprinkle the brown sugar over each of the ramekins. Place pan under grill until sugar has melted and caramelized, about 5 minutes.
Remove ramekins from water bath. Allow to cool for about 15 minutes. I prefer to chill these in the fridge before serving however they are just as heavenly served warm.