Heat olive oil in a large sturdy pot over medium heat. Add beef and brown well. Break up beef as it browns.
Add onions and garlic to the pot and cook for 3-4 minutes until veggies are soft. Season mixture with oregano, mustard, and a pinch of salt and pepper. Stir in tomato paste.
Add diced tomatoes and macaroni pasta. Stir to combine. Then add beef stock and water. Stir, cover, turn heat down to low, and simmer for 12 minutes.
Check pasta. If it’s still uncooked and the pot is dry, add another cup of water, cover, and simmer or another 2-3 minutes. Most likely though the pasta will be cooked through after 12 minutes.
Season pasta mixture with salt and pepper. Add grated cheese to the top of the pasta, cover again, and let steam for 2-3 minutes until cheese is very melted.
Top cheeseburger pasta with chopped scallions and serve while warm!