How to get food from a waiter out to lunch?
'out to lunch?' is the definition.
(I've seen this before)
'how to get food from a waiter' is the wordplay.
I cannot really see how this works, but
'food' could be 'roll' (roll is a kind of food) and 'roll' is present in the answer.
'from' could be 'off' (I've seen this in other clues) and 'off' is found in the answer.
'a' could be 'one' and 'one' is found in the answer.
The remaining letters 'stey' is a valid word 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?
(Other definitions for off ones trolley that I've seen before include "Mad" , "served as a dessert, perhaps?" , "From which one may be served sweet" , "Bananas" , "out to lunch" .)