To soak or souse can give us a treat (8)
I believe the answer is:
saturate
'to soak' is the definition.
(synonyms)
'give us a treat' is the wordplay.
'give' is an anagram indicator (I've seen 'giving' mean this (the letters give the letters for another word)).
'us'+'a'+'treat'='usatreat'
'usatreat' anagrammed gives 'SATURATE'.
'or souse can' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for saturate that I've seen before include "Infuse or fill completely" , "Soak completely" , "steep" , "flood" , "Make thoroughly wet, soak" .)