The Authentic Basque Dinner at a Gastronomic Society
One of the cornerstones of the Basque dining tradition is the gastronomic society. It is a private club whose 'clubhouse' typically consists of a kitchen and a huge dining room. Members bring raw product and join together to cook dinner, eat, and enjoy.
Societies members only are invited to enter, but if you can't befriend a Basque quickly enough, you can contact one of the city's guides and beg for an inside tour. Sometimes it works.