Aromatic paste — mostly strong, is it? (7)
I believe the answer is:
harissa
'aromatic paste' is the definition.
'harissa' can be an answer for 'paste' (I have seen 'hot paste' mean 'harissa' so perhaps 'paste' could also mean 'harissa'). I'm not sure about the 'aromatic' bit.
'mostly strong is it?' is the wordplay.
'mostly strong' becomes 'har' (I can't explain this - if you can you should give a lot more credence to this answer).
'it?' becomes 'sa' (old-fashioned abbreviation for sex appeal).
'har'+'is'+'sa'='HARISSA'
Can you help me to learn more?
(Other definitions for harissa that I've seen before include "Spicy sauce" , "Hot North African sauce" , "Hot paste used in North African cuisine -- ass hair (anag)" .)