A porridge I mixed up for rodent (7,3)
I believe the answer is:
prairie dog
'rodent' is the definition.
(prairie dog is a kind of rodent)
'a porridge i mixed up' is the wordplay.
'mixed up' indicates anagramming the letters.
'a'+'porridge'+'i'='aporridgei'
'aporridgei' is an anagram of 'PRAIRIE-DOG'.
'for' is the link.
(Other definitions for prairie dog that I've seen before include "A ground squirrel" , "Animal" , "Underground community member" , "North American burrowing mammal" , "Rodent" .)