"A type of Spanish vaudeville or operetta, usually satirical in nature," so named for the Palace of Zarzuela, the royal residence of Spain. That's one definition. The other is a dish swimming with clams, mussels, squid, shrimp, and other formerly-swimming things. The recipe says "two ounces Spanish brandy (optional)" but mandatory seems wiser.

Looks pretty good, actually. It's the festive Tower of Lettuce and Shellfish Exoskeletons that sets it apart.