Ingredients:

* 5 tablespoons butter or margarine, cubed
* 1 medium onion, sliced and separated into rings
* 1 1/2 pounds halibut or salmon steaks
* 3/4 cup mayonnaise
* 3/4 cup sour cream
* 3/4 teaspoon garlic powder
* 3/4 teaspoon seasoned salt
* 3/4 teaspoon dried basil
* 3/4 teaspoon dried thyme
* 1/8 teaspoon pepper
* 1/2 cup dry bread crumbs
* 1 cup shredded Parmesan cheese

Methods:

1. Place butter and onion on a double thickness of heavy-duty foil (about 34 in. x 18 in.). Cut fish into serving-size pieces, removing and discarding the bones. Place over the onion.
2. In a bowl, combine the mayonnaise, sour cream and seasonings.Set aside 1/2 cup for serving. Spoon the remaining sauce over fish. Sprinkle with bread crumbs and Parmesan cheese. Fold foil around fish and seal tightly.Grill, covered, over indirect medium heat for 15-20 minutes or until fish flakes easily with a fork.