Definition of au gratin in English:

au gratin

adjective

  • [postpositive] Sprinkled with breadcrumbs or grated cheese and browned.

    ‘lentil and mushroom au gratin’
    • ‘I used to do a potato au gratin with mushrooms which I really like.’
    • ‘These are the traditional components of potatoes au gratin.’

Origin

French, literally by grating, from the verb gratter to grate.

Pronunciation:

au gratin

/əʊ ˈɡratã//French o ɡʀatɛ̃/