Fat rendered from a roast duck is gold, my friend. By taking this fat and submerging more raw duck in there you can create an entirely new eating experience. If you absolutely have to, substitute the duck fat with the equivalent amount of olive oil. While not ideal, the duck will still end up delicious. It’s good to know that this is also an amazing way to preserve meat. Once the meat has been in the oven for a few hours, remove and allow to set in the fridge. When the craving hits, pull out some duck and get it into a pan for colour.