Grate the last piece of bread after tea is cooked (11)

'cooked' is the definition.
Both the definition and answer are past participle verbs.
Perhaps you can see a link between them that I don't see?

'grate the last piece of bread after tea' is the wordplay.
'grate' becomes 'grille' (grille is a kind of grate).
'the last piece of' says to take the final letters.
'after' says to put letters next to each other.
'tea' becomes 'char' (I've seen this before).
The final letter of 'bread' is 'd'.
'grille'+'d'='grilled'
'grilled' put after 'char' is 'CHARGRILLED'.

'is' acts as a link.

Can you help me to learn more?