

These images were taken from the Japan_FoodStory video in Sangourmand (Osaka), a Hambagu specialized restaurant that's famous in Japan cause of its surprisingly juicy Hambagus, that "explode" when pierced with chopsticks, and its black demiglace sauce.
In the video, meat proportions are explained, but the blend of spices, sauces and vegetables remains a secret. I know Hambagu usually uses a mix of onion, nutmeg, panko, egg and sometimes worcestershire sauce, milk or even some mayonnaise, but the mix seen in the image is darker and more brown that you would expect from those ingredients. What do you think is being kept as a secret here? Are there any other classic ingredients I have not considered? Have you ever tried this Hambagu and noticed any possible ingredients?
Japan_FoodStory video: https://youtu.be/8Ja1hNNLJko?si=zEIo5LPWJtCmKLLl
HyoFood video: https://youtu.be/zNQA6AFSbPM?si=oC3ci_usvByDun7t
by Jsanalvrez