Crossword Genius

Spot what some would see as a seaside street treat (5)

Ross

I believe the answer is:

whelk

I'm a little stuck... Click here to teach me more about this clue!

'treat' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Maybe they are linked in a way I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for whelk that I've seen before include "Shellfish" , "Edible marine snail" , "Sea snail" , "Carnivorous mollusc" , "Spiral-shelled mollusc" .)

I've seen this clue in The Times and The Sunday Times.
Want a hint initially instead of a full solution? Install my app