Itchy feet turned red when covered with ground walnuts (10)
I believe the answer is:
wanderlust
'with ground walnuts' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'itchy feet turned red when covered' is the wordplay.
I cannot quite see how this works, but
an anagram of 'red' is 'der' which is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for wanderlust that I've seen before include "travel bug" , "An urge to stray" , "Restlessness" , "Strong desire to travel" , "Urge to travel" .)