Sauce prepared again, essence not originally being included (9)

'sauce' is the definition.
(I know that remoulade is a type of sauce)

'prepared again essence not originally being included' is the wordplay.
'prepared again' becomes 'remade' ('made' can be a synonym for 'prepared' so perhaps 'remade' is OK for 'prepared again').
'essence' indicates the central letters (I've seen 'essence of' mean this).
'originally' becomes 'ul' (I can't justify this - if you can you should believe this answer much more).
'being included' means one lot of letters goes inside another.
The central letter of 'not' is 'o'.
'o'+'ul'='oul'
'remade' enclosing 'oul' is 'REMOULADE'.

Can you help me to learn more?