Bacalao a la Vizcaína

This recipe closely follows the version given by Nicolasa Pradera in her book La cocina de Nicolasa (1961). Note that the very slow and long cooking of the onions is essential to produce the authentic flavour (although a short-cut is obviously possible here). I mention also that Bacalao a la Vizcaína is often made with tomatoes as well. But the dish should then, strictly speaking, be known as Bacalao a la Riojana.