Large eggs with breakfast, lunch, and elevenses initially appealing (7)
I believe the answer is:
lovable
'appealing' is the definition.
(thesaurus)
'large eggs with breakfast lunch' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'eggs' becomes 'ova' (term for egg cells).
'with' means one lot of letters go next to another.
'breakfast lunch' becomes 'ble' (I can't justify this - if you can you should believe this answer much more).
'l'+'ova'+'ble'='LOVABLE'
'and elevenses initially' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for lovable that I've seen before include "Adorable" , "Inspiring affection" , "Easy to be fond of like 21 Down" , "Attracting affection" , "Delightful" .)