The most common and most likely answer to this crossword clue is the 5 letter word GOOSE
I've seen this crossword clue in The Daily Telegraph
G
O
O
S
E
More clues leading to the result GOOSE
- . Fool may be unwelcome pain in the backside
- Could be a barnacle‘s inappropriate prod
- Travel round south-eastern Falklands Green
- Bird goes savage protecting egg
- Waterfowl, say, including small ducks on the rise
- Sticky stuff almost became solid? Fool!
- Bird goes wild protecting egg
- 1 retiring, say, getting very old
- Mother who rhymes ‘sticky sludge’ with ’empty sludge’
- Elk’s good for starter, and this should be cooked!
Buddy explains!

The straight part
We know that "this should be cooked" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this should be cooked = goose.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 GOOSE mean?
GOOSE noun- Any of various grazing waterfowl of the family Anatidae, which have feathers and webbed feet and are capable of flying, swimming, and walking on land, and which are bigger than ducks.
- A female goose (sense 1).
- The flesh of the goose used as food.
- A silly person.
- A tailor's iron, heated in live coals or embers, used to press fabrics.
- A young woman or girlfriend.
- An old English board game in which players moved counters along a board, earning a double move when they reached the picture of a goose.
- To sharply poke or pinch someone's buttocks. Derived from a goose's inclination to bite at a retreating intruder's hindquarters.
- To stimulate, to spur.
- To gently accelerate an automobile or machine, or give repeated small taps on the accelerator.
- (UK slang) Of private-hire taxi drivers, to pick up a passenger who has not pre-booked a cab. This is unauthorised under UK licensing conditions.
- To hiss (a performer) off the stage.