Béarnaise sauce
Concise Oxford English Dictionary © 2008 Oxford University Press:
Béarnaise sauce /ˌbeɪəˈneɪz/
▶noun a rich sauce thickened with egg yolks and flavoured with tarragon.
– origin Béarnaise, fem. of Fr. béarnais ‘of Béarn’, a region of SW France.
'Béarnaise sauce' also found in these Oxford entries:

