1. Place potatoes in a large saucepan and cover with water. Bring to a boil. Reduce heat; cover and cook for 15-20 minutes or until tender. Drain.
2. In a small bowl, beat the potatoes, milk and butter until blended. Stir in 1/2 cup cheese, 3 tablespoons bacon bits, garlic powder and salt.
3. Transfer to a 1-qt. baking dish coated with cooking spray. Sprinkle with remaining cheese. Top with onion and remaining bacon. Bake, uncovered, at 350° for 15-20 minutes or until heated through and cheese is melted. Yield: 4 servings.