Rough and ready eggy starters are undercooked (4)
I believe the answer is:
rare
'undercooked' is the definition.
(thesaurus)
'rough and ready eggy starters' is the wordplay.
'starters' indicates taking the first letters.
The first letters of 'rough and ready eggy' is 'RARE'.
'are' is the link.
(Other definitions for rare that I've seen before include "Meat that's lightly cooked" , "Scarcely seen" , "Very lightly cooked, meat say" , "Very scarce, hardly cooked" , "Seen once in a blue moon" .)