Flavouring from Switzerland I have to pursue (5)
I believe the answer is:
chive
'flavouring' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'switzerland i have to pursue' is the wordplay.
'switzerland' becomes 'ch' (short for Confoederatio Helvetica, its Latin name).
'i have' becomes 'ive' (contraction of 'I have').
'to pursue' says to put letters next to each other.
'ch'+'ive'='CHIVE'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for chive that I've seen before include "12 down-like herb" , "Onion-like herb" , "Herb of onion family" , "Leaves" .)