The staff - and most of the diners - are dressed in black-and-white in sympathy, and it's probably no accident that by far the most popular of the 80 immaculately presented tortillas on the menu is the colour-coded morcilla de arroz de Burgos: black sausage and white rice.
And in my chorizo-and-shrimp rice, a dish inspired by my travels in Spain, kelp stock magnifies the umami impact of the sausage and shellfish and the briny character of the clam juice that the rice simmers in.