From Tolkien Gateway
This article describes a concept which is mentioned in J.R.R. Tolkien's works, but was never given a definite name.

Earth-bread was an edible root known only to the Dwarves. It was white and fleshy and after boiling was good to eat and similar to bread. Its name in the dwarf-tongue is unknown.[1]:p. 134

When Túrin and his outlaw band encountered Mîm and his sons, the Petty-dwarves were carrying sacks of the plants,[1]:p. 123 and possibly gold ingots disguised as roots.[2] Later, at the hideout of Bar-en-Danwedh, Mîm contributed his earth-bread to the food supply of the outlaws, although he refused to share with Ulrad, who had insulted him.[1]:pp. 134-135

See also