Heat a large skillet over medium-high heat and juts a bit of oil and once hot add the ground beef and onion, cook 5-7 minutes, until beef is browned, breaking it down with a wooden spoon. Frain the grease.
Add garlic and cook for 1-2 minutes.
Reduce heat to medium and add marinara sauce, diced tomatoes, tomato paste, broth, Italian seasoning, Worcestershire sauce, thyme, basil, oregano, salt, pepper, and brown sugar. Stir to combine.
Transfer the mixture into a lightly greased 6-quart slow cooker.
Top with the broken spaghetti and stir to combine.
Top with shredded cheese, cover, and cook on LOW for 4 hours.
Serve garnished with fresh parsley or basil and with a sprinkle of grated Parmesan cheese.
