1. First, take the juice that comes out of the belly of the roasted duck, add an appropriate amount of thick stock (if there is no stock, just use boiling water), and add the duck's trimmings, such as duck feet and wings. Wait for appropriate amount.

2. Bring to a boil and simmer for a while.

3. Add roast duck ingredients, soy sauce, oyster sauce, chicken essence, ginger, onion and garlic, and cook for a while.

4. Finally, add a little cornstarch to thicken the soup, and a fragrant roast duck sauce is ready!

5. If you like roast duck sauce with a slightly darker color, you can add an appropriate amount of dark soy sauce to adjust the color.