Perhaps, Dean's cool mischievous streak (3-6)
I believe the answer is:
ice-skater
'perhaps dean's' is the definition.
I can't tell whether this defines the answer.
'cool mischievous streak' is the wordplay.
I cannot quite understand how this works, but
'cool' could be 'ice' (icing is a kind of cooling) and 'ice' is found within the answer.
an anagram of 'streak' is 'skater' which is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ice-skater that I've seen before include "Torvill or Dean, say" , "One gliding over rink" , "Dean for one" , "Winter sportsperson" , "Person gliding on frozen water" .)