Boil spaghetti in salted water until al dente; drain.
Heat olive oil in a skillet, sauté diced onion and garlic paste for 2 minutes.
Add ground beef and cook until fully browned, breaking into small crumbles.
Pour in tomato sauce, dried oregano, black pepper, and salt; simmer for 15 minutes.
Toss cooked spaghetti into the sauce and serve hot sprinkled with parmesan cheese.