Cook ground beef and onion in a large skillet over medium heat, breaking up the beef into small crumbles with a wooden spatula as it cooks.
Cook until the beef is cooked through and onions are soft. Drain off any excess grease.
Add tomato paste to the pan and combine with the beef and onion in the skillet. Cook for about a minute.
Add the minced garlic and cook for another minute, until garlic is fragrant.
Add salt, pepper, mustard and smoked paprika to the skillet. Stir to combine with the beef.
Add the Worcestershire sauce and can of beef broth. Stir in 2 cans of water and stir to combine everything in the skillet.
Add all the noodles and stir to coat them with the beefy sauce mixture.
Cover the pan and reduce heat to low. Simmer for 10 minutes or until noodles are tender, stirring occasionally to prevent burning.
Stir in the sour cream and stir to combine. Cook for a minute or two until everything is heated through.
Serve garnished with sliced green onions.