Tried hard to get supper finally in oven (6)
I believe the answer is:
strove
'tried hard' is the definition.
(past tense of 'strive')
'supper finally in oven' is the wordplay.
'supper finally' becomes 'r' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'oven' becomes 'stove' (I've seen this before).
'r' inserted into 'stove' is 'STROVE'.
'to get' acts as a link.
(Other definitions for strove that I've seen before include "Made great efforts" , "Endeavoured" , "Struggled" , "Tried hard for voters" , "Voters (anag) - made every effort" .)