In a heavy-bottomed saucepan over medium heat, add Heavy Cream (3 cup) and Vanilla Extract (2 teaspoon). When mixture starts to form bubbles, remove it from the heat.
In a mixing bowl, add Egg (6) and Caster Sugar (1/2 cup). Whisk together.
Add the heavy cream mixture very slowly to the egg mixture, whisking as you go. Pass the cream through a strainer into a clean mixing jug. Use a spoon to skim any bubbles from the top of the mixture.
Arrange ramekins in a baking pan filled halfway with hot water. Divide Nutella® (4 tablespoon) evenly into the bottom of each ramekin. Pour the cream mixture over top.
Bake at 300 degrees F (150 degrees C) for 40-45 minutes, or until creme brulee is set but jiggly in the center.
Place creme brulee in fridge for 2-3 hours.
Top with Brown Sugar (4 tablespoon), spreading the sugar into an even layer.
Cook the creme brulee under the broiler on high until brown sugar has caramelized and hardened.