Number having large bit of cake (5)
I believe the answer is:
flour
'bit of cake' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'number having large' is the wordplay.
'number' becomes 'four' (four is a kind of number).
'having' is an insertion indicator.
'large' becomes 'L' (eg in clothes sizes).
'four' going around 'l' is 'FLOUR'.
Can you help me to learn more?
(Other definitions for flour that I've seen before include "Ground wheat" , "Powdered grain" , "Powder for cooking" , "Main ingredient of bread" , "Cake ingredient" .)