Charcoal is so in right now.
And Burger King is on the trend. In Japan, it's is possible to order black burgers called “The Kuro Pearl,” and “The Kuro Diamond" which appear to have a black bun, black sauce and black cheese.
“The black color of the bun is achieved by using bamboo charcoal, and
the black sauce is created with squid ink.”
Hmmm, don't mind if I pass.