Blackrock Stew

Blackrock Stew is the reward of the quest Dragon Food given out by the Bane Chosen Bounty Collector for those who have more than 2000 loyalty points towards Bane Chosen side during the In the Shadow of Virtue - Rise of the Bane Chosen. It can't be used by the player:

You don't want to eat this, it smells horrible. It looks like food for some kind of demon.

It is the only known food for the Bane Dragon. As such, it is a single-use item that is dropped on the Bane Dragon.