In a large pan, combine ground chuck, onion, bell pepper and garlic.
Cook over medium-high heat for 8 to 10 minutes, stirring occasionally until beef is browned and crumbles.
Drain well.
Stir in thyme, brown sugar, broth, diced tomatoes, tomato sauce, Italian seasoning, and salt into cooked meat mixture.
Bring to a boil over medium-high heat; reduce heat and simmer 20 minutes.
Add noodles, and simmer until noodles are tender.
Preheat broiler.
Ladle soup into 8 to 10 ovenproof bowls.
Evenly sprinkle with mozzarella cheese.
Broil soups, 6-inches from heat, 3 to 4 minutes, until cheese is browned and bubbly.