Mark-up on revolutionary Gulf country’s dessert (6)
I believe the answer is:
gateau
'country's dessert' is the definition.
The definition and answer can be both things that one consumes for nourishment as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'mark-up on revolutionary gulf' is the wordplay.
'mark' becomes 'tag' (tag is a kind of mark).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'on revolutionary gulf' becomes 'eau' (I am not sure about this - if you are sure you should believe this answer much more).
'tag' backwards is 'gat'.
'gat'+'eau'='GATEAU'
Can you help me to learn more?
(Other definitions for gateau that I've seen before include "Black Forest dessert" , "Creamy dessert cake" , "(French?) cake" , "Gooey cake" , "Calorie-laden cake" .)