French queen ordered one a treat in time (5,10)
I believe the answer is:
marie antoinette
'french queen' is the definition.
'marie antoinette' can be an answer for 'queen' (I've seen this before). I'm not sure about the 'french' bit.
'ordered one a treat in time' is the wordplay.
'ordered' indicates anagramming the letters.
'one'+'a'+'treat'+'in'+'time'='oneatreatintime'
'oneatreatintime' anagrammed gives 'MARIE-ANTOINETTE'.
Can you help me to learn more?
(Other definitions for marie antoinette that I've seen before include "Queen, guillotined in 1793" , "She lost her head" , "French queen, d.1793" , "unpopular queen" .)