Rolled this around and covered the cake. (4)
I believe the answer is:
dice
'rolled this around and covered the cake' is the definition.
The definition suggests a singular noun which matches the answer.
'rolled this around and covered the cake' is the wordplay.
'rolled' becomes 'pronounced with a roll' ('pronounce with a roll' can be a synonym of 'roll').
'this around' indicates the central letters.
'and' says to put letters next to each other.
'covered the cake' becomes 'ice' (I can't explain this - if you can you should give a lot more credence to this answer).
The central letter of 'pronouncedwitharoll' is 'd'.
'd'+'ice'='DICE'
Can you help me to learn more?
(Other definitions for dice that I've seen before include "Gambling items" , "Make into chips" , "Chop up (food)" , "Small cube" , "Cubes used in gambling" .)