For example Dorothy's served up filling food (6)
I believe the answer is:
stodge
'filling food' is the definition.
(I've seen this in another clue)
'for example dorothy's served up' is the wordplay.
'for example' becomes 'e.g.' (short for 'exempli gratia', 'for example' in Latin).
'dorothy's' becomes 'dot's' (short for Dorothy).
'served up' shows that the letters should be reversed in order (in a down clue, going upwards).
'eg'+'dots'='egdots'
'egdots' back-to-front is 'STODGE'.
(Other definitions for stodge that I've seen before include "Sticky stuff" , "Heavy, uninteresting food" , "Heavy and indigestible food" , "Steamed pudding" , "Heavy solid food" .)