In buttered 13-by-9-inch baking dish or jellyroll pan, lay fillets in single layer. Do not stack fillets. Brush top with juice.
Bake fish in preheated oven 10 to 20 minutes or until fish just starts to flake
In bowl combine cheese, butter, mayonnaise, onions and seasonings. Mix well with fork.
Spread with cheese mixture and bake until golden brown, about 5 minutes. Baking time will depend on the thickness of the fish. Do not overcook.
Note: This fish can also be made in a broiler. Broil 3 to 4 minutes or until almost done. Add cheese and broil another 2 to 3 minutes or until browned.