Heat oven to 375°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray. In large bowl, beat eggs. Stir in pasta sauce, bread crumbs, onion, Italian seasoning, salt and beef until well blended. Press mixture in bottom of baking dish.
Bake 45 to 55 minutes or until meat thermometer inserted in center of loaf reads 160°F.
Meanwhile, make both pouches of mashed potatoes as directed on box, using milk, hot water and butter.
Spoon any excess juices from baking dish. Spread mashed potatoes over meat loaf; sprinkle with cheese. Bake 10 to 15 minutes longer or until top begins to brown. Let stand 5 minutes before cutting.