Baked Salmon with Creamy Dill Sauce

1. Line a 15-inch x 10-inch x 1-inch baking pan with heavy-duty foil; grease lightly. Place salmon skin side down on foil. Sprinkle with lemon-pepper, onion powder, and garlic salt.
2. Top with sliced onion and lemon and dot with butter. Fold foil around salmon; seal tightly.
3. Bake at 350°F for 20 minutes. Open foil carefully, allowing steam to escape and cook an additional 5 minutes,
4. In a small bowl combine the remaining ingredients (sour cream, mayo, dill, lemon juice, horseradish, chopped onion, and garlic salt/pepper).
5. Cut salmon into individual portions and top with creamy dill sauce. Serve with favorite side dishes.