The most common and most likely answer to this crossword clue is the 7 letter word REHEATS
I've seen this crossword clue in The Guardian
R
E
H
E
A
T
S
Buddy explains!
The straight part
We know that "Puts back in the oven" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case puts back in the oven = reheats.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does REHEATS mean?
REHEATS noun- An afterburner.
- To heat something after it has cooled off, especially previously cooked food (also in figurative senses).
- To become hot again after having cooled off (also in figurative senses).
- Alternative form of rehete