Simply place salted duck eggs into a pot with water and turn on medium heat. Let it boil for about 15 minutes. Or, cook the salted duck eggs in the instant pot pressure cooker for 5 minutes at high pressure and natural release pressure. Then, soak them into the ice bath.  If you use the raw salted yolks for mooncake, you will need to bake them before wrapping them into a mooncake. Preheat the oven to 325 F, place the salted duck yolk on the tray with a parchment paper. Sprinkle some cooking rice wine and bake it for 8 minutes. Then, let it completely cool off before using it.