Eat whole amount in thing holding ice cream (7)
I believe the answer is:
consume
'eat whole' is the definition.
'consume' can be an answer for 'eat' (consuming is a kind of eating). I'm unsure of the 'whole' bit.
'amount in thing holding ice cream' is the wordplay.
'amount in thing' becomes 'sum' (I can't justify this - if you can you should give a lot more credence to this answer).
'holding' indicates putting letters inside.
'ice cream' becomes 'cone' (cone can refer to an ice cream cone).
'sum' going inside 'cone' is 'CONSUME'.
Can you help me to learn more?
(Other definitions for consume that I've seen before include "Use up" , "Eat, drink" , "Exhaust" , "Devour" .)