“I think that there is more in the bun than A1 sauce to make it black.”
Yep, they have been busted. I guess food colouring. I want a healthier choice! ;)
How do you make black out of food coloring?
https://answers.yahoo.com/question/index?qid=20061030125603AAc2VDJ
I figured since it originated in Japan they probably used squid ink there to make the buns black and I wondered what they would substitute here.