Cereal covers uniform in nasty slime (6)
I believe the answer is:
muesli
'cereal' is the definition.
(I know that muesli is a type of cereal)
'uniform in nasty slime' is the wordplay.
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' means one lot of letters goes inside another.
'nasty' indicates anagramming the letters (a nasty or wrong spelling).
'slime' anagrammed gives 'mesli'.
'u' going within 'mesli' is 'MUESLI'.
'covers' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for muesli that I've seen before include "Granola-like food" , "Breakfast mixture of oats, nuts, fruit etc" , "Mule is fed with breakfast compound" , "Breakfast food of cereals, fruits, nuts etc" , "Cereal made with oats and nuts" .)