Cereal for Emil and us? Rubbish! (6)
I believe the answer is:
muesli
'cereal' is the definition.
(I know that muesli is a type of cereal)
'emil and us? rubbish' is the wordplay.
'and' says to put letters next to each other.
'rubbish' is an anagram indicator (a poor quality or rubbish spelling of the letters).
'emil' after 'us' is 'usemil'.
'usemil' with letters rearranged gives 'MUESLI'.
'for' acts as a link.
(Other definitions for muesli that I've seen before include "Breakfast food of cereals, dried fruit, nuts etc" , "Dish of dried fruit and cereals" , "Breakfast cereal mix" , "Breakfast mix of oats, nuts, fruit etc" , "Breakfast dish with cereals, nuts, fruit etc" .)