Warm 5 cinnamon sticks, 2 split whole nutmeg, 1 whole vanilla bean, 2 teaspoons whole black pepper, 2 star anise, 2 teaspoons of juniper berries, 1 teaspoon of cardamom, and 2 teaspoons of cloves in a large saucepan over medium heat.
Once warmed, remove from the heat and turn off the stove. It is crucial that the heat source has been turned off before introducing the whiskey so as to avoid a fire hazard.
Pour 1 litre of whiskey over the cardamom and cloves and let them steep for one hour.
Add the remaining spices and let them all steep together for an additional hour.