The most common and most likely answer to this crossword clue is the 4 letter word OVEN
I've seen this crossword clue in The Times
O
V
E
N
More clues leading to the result OVEN
- Kitchen heater tested in couple's absence
- Old archdeacon’s kitchen appliance
- Even a dory somehow can be prepared for roasting
- Wretched envoy clutching register prepared for a probable roasting
- Baker, having finished, runs out at noon
- Cooker of very exquisite nosh
- Range one voluntarily holds back
- Almost completed northern range
- Kitchen heater tested in couple’s absence
- Archdeacon after the heart of Tom Baker?
Buddy explains!

The straight part
We know that "Kitchen heater" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case kitchen heater = oven.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 OVEN mean?
OVEN noun- A chamber used for baking or heating.