Sides of ricotta cheese react to yeast (4)
I believe the answer is:
rise
'sides of ricotta cheese' is the definition.
The definition and answer can be both to do with fundamental existence as well as being verbs in their base form.
Perhaps there's an association between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for rise that I've seen before include "Move upward" , "Salary increase" , "Provide (an opportunity)" , "Soar" , "Get out of bed, sire" .)