1. Preheat oven to 350. 2. Grease a casserole or 9x13 baking dish with nonstick cooking spray and set aside. 3. In a large skillet, cook beef until browned. Drain grease. 4. Meanwhile, cook pasta until el dente. Drain and mix pasta with butter. 5. Stir in beef, tomato sauce and 2 cups of cheese. Season with salt and pepper. 6. Pour into prepared dish. 7. Sprinkle top with remaining 1/2 cup cheese. Bake for 25-30 minutes or until hot in the center.