Step 1

Lay out the cooked salted duck egg yolks evenly on a baking sheet lined with parchment paper. Using cooked salted duck yolks sold in vacuum-sealed packages is the most economical option. Bake for 10 minutes, until they begin to release oil. Cool completely.

Step 2

If you are using homemade, raw salted duck egg yolks, crack open the eggs and remove the yolks. Under a gentle stream of water, rinse the yolks clean of any white. Roll each yolk in 1 teaspoon Shaoxing wine or Baijiu (Chinese hard liquor) if you have it. Lay them out on a baking sheet and bake them at 350°F for 15 minutes, or until they start to release oil. Cool completely.

Step 3

Transfer the yolks to a food processor, and pulse until they have a very fine, powder-like consistency.

Step 4

Add the oil, sugar, salt (if using), and powdered yolks to a nonstick pan set over medium/low heat. Stir and cook for 8-10 minutes, until the sauce is bubbling very slightly around the perimeter of the pan. Do not use high heat, or the sauce may burn.

Step 5

Cool, and store in a clean, air-tight container. It will keep in the refrigerator for 1 month as long as you use a clean utensil to scoop out what you need each time. (Cross contamination shortens the shelf life of anything).