At last! Commanding Officer back in Pacific island capital for some root starch (7)
I believe the answer is:
tapioca
'starch' is the definition.
(I know that Tapioca is a type of cassava starch)
'at last commanding officer back in pacific island capital' is the wordplay.
'last' suggests the final letters.
'commanding officer' becomes 'co'.
'back' is a reversal indicator.
'in' means one lot of letters goes inside another.
'pacific island capital' becomes 'apia' (I've seen this in another clue).
The last letter of 'at' is 't'.
'co' back-to-front is 'oc'.
'oc' going within 'apia' is 'apioca'.
't'+'apioca'='TAPIOCA'
'for some root' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tapioca that I've seen before include "Starchy food" , "pud" , "Ciao, Pat, have some strange pudding" , "Hard white cassava grains used for puddings" , "Pudding made from an extract of cassava" .)