The most common and most likely answer to this crossword clue is the 3 letter word FRY
F
R
Y
More clues leading to the result FRY
Buddy explains!

The straight part
We know that "food items at greasy spoon?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case food items at greasy spoon? = fry.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 FRY mean?
FRY noun- (usually in the plural, fries) A fried strip of potato.
- A meal of fried sausages, bacon, eggs, etc.
- A state of excitement.
- A method of cooking food.
- To be affected by extreme heat or current.
- Offspring; progeny; children; brood.
- Young fish; fishlings.
- A swarm, especially of something small.
- The spawn of frogs.
- A kind of sieve.
- A drain.