A 1950s article in French describes how the corms of Arum maculatum
are prepared for food. The species is known in England as
Lords-and-ladies or Cuckoo-pint.

They are said to be prepared according to the methods used in South
America to prepare 'couac'.

Does anybody have any idea what 'couac' is, remembering the article is
in French?

I wonder whether the reference is to an unrelated plant Manihot
utilissima (manioc, yuca. cassava).