In a large skillet, brown the ground beef along with the chopped onion and minced garlic, breaking up the meat as it cooks. Drain off any excess fat.
Add meat, onion, and garlic to your slow cooker and turn heat to high or low (depending on how quickly you want it to cook).
Add the salt, black pepper, paprika, oregano, basil, marjoram (or Italian seasoning mix), tomato paste, diced tomatoes (undrained), and broth and stir to incorporate. (I like to mash the paste with my spoon or spatula to blend it into the rest of the ingredients.)
Cook on high for 3-4 hours or low for 5-6 hours.
During the last 30 minutes of cook time, you will add the uncooked pasta and turn the heat down to low (if it was on high). Cover and let cook 30 minutes.
Once pasta is done, turn heat off, add the shredded cheese, and cover for another 5-10 minutes or until cheese is melty. Serve right away.