Piquant, brown and grey on the outside (5)
I believe the answer is:
tangy
'piquant' is the definition.
(I've seen this before)
'brown and grey on the outside' is the wordplay.
'brown' becomes 'tan' (tan is a kind of brown).
'and' means one lot of letters go next to another.
'on the outside' says to hollow out the word (remove centre letters).
'grey' with its middle taken out is 'gy'.
'tan'+'gy'='TANGY'
(Other definitions for tangy that I've seen before include "Piquant" , "Sharp-tasting" , "characterised with relish?" , "Piquantly flavoured" .)