What a careless person might do when making sandwiches (13)
I believe the answer is:
butterfingers
'what a careless person' is the definition.
(I've seen this before)
'might do when making sandwiches' is the wordplay.
I cannot quite see how this works, but
'do' could be 'ut' (synonyms) and 'ut' is located in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for butterfingers that I've seen before include "Hopeless catcher" , "Person continually dropping things" , "Someone prone to dropping things" , "who keeps spilling things" , "He can't catch for toffee!" .)