Heat the olive oil in a large, heavy-based frying pan over medium heat.
Add the onion, garlic, carrots, celery and salt and cook for 3 minutes or until tender.
Add the beef mince and cook for a further 3 minutes, breaking up the beef as you go, until browned.
Stir through the pepper, onion powder, oregano and sugar.
Add the tomato paste and cook for 1 minute.
Add the beef stock and crushed tomatoes and bring to a simmer.
Add the pasta, cover with the lid, and simmer for 15 minutes, stirring occasionally.
Add the milk and cheese and stir until cheese has melted.
Season to taste.
Add mozzarella on top, replace the lid, and leave to sit for 30 seconds until melted.
Sprinkle with parsley and serve!