Mix for a Hamburger – I will be covered in mush (8)
I believe the answer is:
pastiche
'mix' is the definition.
(thesaurus)
'covered in mush' is the wordplay.
'covered' becomes 'ich' (I can't explain this - if you can you should believe this answer much more).
'in' indicates putting letters inside.
'mush' becomes 'paste'.
'ich' placed into 'paste' is 'PASTICHE'.
'for a hamburger i will be' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for pastiche that I've seen before include "Imitative artwork" , "Work imitating various sources" , "Work of mixed styles" , "Work of art that imitates the style of a previous work" , "Imitative work of art" .)