Bilbao is another league. Small differences aside, it reminds me greatly of l'Havana, even though in Bilbao you'll find some more modern dishes.
The fried eggs with foie and Pedro Ximenez (a type of Sherry), is a clasic here. Bilbao's stews are like honey in the mouth. The cod and the mixed "trinxat" (typical cabbage with potato) are delicious as well.
The menu is awkward as you don't really know how to approach it, but there are choices for everyone. The restaurant has that old-fashioned air that brings you back in time. The wine list is quite complete but the glasses are far from correct in some cases.
All in all, it's a restaurant you should expect to eat very well, the sort of place you could safely bring your parents, grandparents, you sons and daughters.