Extremely full? Offer third piece of toast and margarine (5)
I believe the answer is:
flora
'margarine' is the definition.
(I know that Flora is a type of margarine)
'extremely full? offer third piece of toast' is the wordplay.
I cannot really see how this works, but
'piece' could be 'r' (abbreviation for Rook) and 'r' is present in the answer.
'of' could be 'o' and 'o' is found in the answer.
'offer third' could be 'f' (3rd letter of 'offer') and 'f' is found within the answer.
The remaining letters 'la' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'and' acts as a link.
Can you help me to learn more?
(Other definitions for flora that I've seen before include "Plants of a region or age" , "growth" , "__ MacDonald, heroine of the 1745 Jacobite rising" , "Various plants" , "local plants" .)