Set your oven to broiler mode at 260 degrees C fan (max setting on my oven)
In a large mixing bowl, add the duck legs, vinegar and ginger. Rub the ingredients all over the duck, to remove any gamey smell.
Rinse the duck and pat dry.
In a clean large mixing bowl, add the duck legs, five spice powder, dark soy sauce, oyster sauce, reserved ginger juice, shallots and garlic, and toss to coat evenly. Marinate in the fridge for about 30 minutes.
While marinating the duck, begin preparing the soup. In a large bowl, soak the red dates, goji berries and mushrooms in water.
Shake off any excess marinade from the duck, and place skin-side up on a wired rack over a lined baking tray.
Transfer the duck to the oven and broil, until skin is blistered and golden, 10 minutes.
While the duck legs are in the oven, rinse and drain the red dates, goji berries and mushrooms. Add the ingredients to your pressure cooker pot.
Add the coconut water, star anise, black cardamom, coriander, soy sauce, dark soy sauce, oyster sauce, ginger, garlic cloves, shallots, onion and carrots. Bring the mixture to a boil using the Saute/Sear (High Temp) function or equivalent.
After the duck legs have been broiled, transfer the duck legs to the pressure cooker pot, and the duck bones if using.
Close and lock the lid and cook, using the Meat/Poultry setting or equivalent, 30 minutes.
When the timer is up, let the pressure release naturally. Carefully unlock and remove the lid, and skim off any excess fat from the liquid.
Add the rock sugar if using, and adjust seasonings to taste, adding the fish sauce if necessary.
Bring a large pot of water to a boil.
Add the siew pak choy and cook, 30 seconds. Remove from the water.
Add the noodles and cook, 1 minute. Do not overcook. Remove from the water and rinse briefly under running cold water to remove excess starch and prevent the noodles from clumping up.
In deep bowls, add the noodles and blanched siew pak choy.
Place a duck leg in each bowl.
Ladle the hot soup into the bowls, topping each bowl with a couple of mushroom caps.
Garnish with the green onions and cilantro. Serve immediately.