Bagel flipping ass leaves in the kitchen (7)
I believe the answer is:
oregano
'leaves in the kitchen' is the definition.
(herbs used when cooking)
'bagel flipping ass' is the wordplay.
'bagel' becomes 'O' (circular).
'flipping' shows that the letters should be reversed in order.
'ass' becomes 'onager' (type of wild ass).
'onager' back-to-front is 'regano'.
'o'+'regano'='OREGANO'
(Other definitions for oregano that I've seen before include "leaves for season" , "Herb used in cookery" , "Pizza herb" , "Gear Ono up for the herb" , "Type of herb" .)