- 1 onion, chopped
- 1/2 pound shredded Cheddar cheese
- 2 pounds swai fish
- 1 teaspoon butter
- 1 cup milk
- 1 1/2 teaspoons Worcestershire sauce
- 1 teaspoon mustard
- 1 teaspoon salt
- ground black pepper to taste
- Preheat oven to 350 degrees F (175 degrees C). Grease a 9×13-inch baking dish.
- Mix onion and Cheddar cheese together in a bowl. Sprinkle 1/2 of the cheese mixture into the prepared baking dish; top with swai fish. Sprinkle the remaining cheese mixture over fish.
- Whisk milk, Worcestershire sauce, mustard, salt, and black pepper together in a bowl; pour over fish.
- Bake in the preheated oven until fish flakes easily with a fork and the cheese is melted, about 45 minutes.