chateaubriand
Concise Oxford English Dictionary © 2008 Oxford University Press:
chateaubriand /ˌʃatəʊˈbriːɒ̃/
▶noun a thick fillet of beef steak.
– origin C19: named after the French writer and statesman François-René, Vicomte de Chateaubriand, whose chef is said to have created the dish.
'chateaubriand' also found in these Oxford entries:

