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. 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. Cook for 3 minutes, turn the pieces over, and cook for 3 more minutes until golden brown.