While visiting San Diego a number of years ago, I fell in love with fish tacos, that city's signature dish.
Cabbage makes a crunchy and nutritious alternative to the iceberg lettuce normally used in tacos.
Like most tacos, this one is a little messy to eat, so have plenty of napkins around. Put the oil in a large, heavy skillet over medium-high heat. Combine the beer, egg, and flour in a medium-size mixing bowl. Stir in the mustard, cayenne, salt, and several grindings of black pepper. Put 6 pieces of fish in the batter, coat well, and add to the skillet.