Tosses terrific toppings on the seafood (7)
I believe the answer is:
lobster
'seafood' is the definition.
(I know that lobster is a type of seafood)
'tosses terrific toppings on the' is the wordplay.
'tosses' becomes 'lobs' (I've seen this in another clue).
'terrific toppings' becomes 'er' (I can't justify this - if you can you should believe this answer much more).
'on' is a charade indicator (letters next to each other).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'er' after 't' is 'ter'.
'lobs'+'ter'='LOBSTER'
Can you help me to learn more?
(Other definitions for lobster that I've seen before include "Tommy no longer" , "Large edible crustacean" , "Large marine decapod" , "potted" , "one for the pot?" .)