Quiche has a new pattern (6)
I believe the answer is:
tartan
'pattern' is the definition.
(I have seen 'Pattern of clan' mean 'tartan' so perhaps 'pattern' could also mean 'tartan')
'quiche has a new' is the wordplay.
'quiche' becomes 'tart'.
'has' says to put letters next to each other.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'tart'+'a'+'n'='TARTAN'
(Other definitions for tartan that I've seen before include "Symbol of the Scottish clans." , "Scots plaid" , "Clan fabric" , "Criss-cross pattern" , "Highland check pattern" .)