French cheese sandwiches dry, large and fragile (7)
I believe the answer is:
brittle
'fragile' is the definition.
(I've seen this before)
'french cheese sandwiches dry large' is the wordplay.
'french cheese' becomes 'brie' (I've seen this in another clue).
'sandwiches' means one lot of letters goes inside another (inserted letters are sandwiched in).
'dry' becomes 'tt' (abbreviation for teetotal).
'large' becomes 'L' (eg in clothes sizes).
'tt'+'l'='ttl'
'brie' enclosing 'ttl' is 'BRITTLE'.
'and' acts as a link.
(Other definitions for brittle that I've seen before include "Easily cracked or snapped" , "Fragile" , "Hard but easily broken" , "Liable to snap" , "Hard but liable to break easily" .)