The most common and most likely answer to this crossword clue is the 7 letter word RAREBIT
I've seen this crossword clue in The Daily Telegraph
R
A
R
E
B
I
T
More clues leading to the result RAREBIT
- Unusual coin found in food
- Cheese on toast a little undercooked?
- Two groups of soldiers chewed toastie
- Dish, exquisite, and then some
- Snack as two Italian rivers rise
- Dish, lightly cooked portion
- Unusually good mouthful — that's cheese on toast!
- Consumable product of melting numismatist’s prize?
- Savoury dish, lightly cooked, cut into
- Valuable coin found in item of food
Buddy explains!

The straight part
We know that "food" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case food = rarebit.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 RAREBIT mean?
RAREBIT noun- Welsh rarebit