BEREAVING

A toughie !

Thinking out loud:
-- anagram: BEAVERING
-- add another E and get BEE VINEGAR (mix in honey and ferment)
-- E-->D gives ADVERBING (You can verb a noun, can't you? Here, just make "questionable" into "questionably")
-- drop the V and get a BRAIN EEG (oops, two words, violates the Roolz)
-- A-->O OVERBEING (God only knows if that's allowed)

But my Final Answer is

V-->U

AUBERGINE