Marcel chewed over a toffee (7)
'toffee' is the definition.
(I've seen this before)
'marcel chewed over a' is the wordplay.
'chewed' indicates an anagram.
'over' is an insertion indicator.
'marcel' is an anagram of 'carmel'.
'carmel' placed around 'a' is 'CARAMEL'.
(Other definitions for caramel that I've seen before include "Burnt sugar used for flavouring" , "It's produced by heating sugar until brown" , "Sugar solution heated till brown" , "Dark brown substance" , "Soft sweet" .)
'toffee' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's a link between them I don't understand?
'marcel chewed over a' is the wordplay.
'chewed' is an anagram indicator.
'over' is an insertion indicator.
'marcel' is an anagram of 'cermal'.
'cermal' going around 'a' is 'CERAMAL'.
Can you help me to learn more?