Small amount of money when cutting cake evenly (5)

'cutting cake evenly' is the definition.
I can't tell whether this definition defines the answer.

'small amount of money when' is the wordplay.
I cannot quite see how this works, but
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is present in the answer.
'amount' could be 'pa' (Pa is an example) and 'pa' is located in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
A single letter 'i' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?