1 tsp (5 mL) salt (optional)

2 tbsp (30 mL) melted butter

2 whole eggs, beaten

1 cup (250 mL) beer

2 egg whites, stiffly beaten

Vegetable oil, for deep-frying

1 lb (500 g) fresh U.S. Farm-Raised Catfish fillets

2 large onions, thinly sliced and separated into rings

Tartar sauce, for serving

Sift flour and salt, if using, into bowl. Stir in melted butter and 2 whole eggs. Gradually add beer and stir until batter is smooth. Let batter stand in warm place for 1 hour, then fold in beaten egg whites.
Fill large, deep heavy pot half full with vegetable oil. Heat the oil to 350°F (180°C).
Dip the catfish in the beer batter and cook two-at-a-time in the hot oil for 3 to 4 minutes per side, or until golden brown and the fish flakes easily when tested with a fork. Drain on paper towels.
Dip the onion rings in the batter and fry them in batches until golden brown, about 2 minutes per side. Drain on paper towels and sprinkle with salt (optional). Serve the catfish and onion rings immediately with tartar sauce, if desired.