Heat the oil in a pan and fry the onion until golden.
Add the mince and cook until browned.
Add the tomatoes and the tomato puree. Blend the contents of the Knorr Mealmaker sachet with the water and add to the mince.
Bring to the boil, stirring continuously. Cover and simmer for 15 minutes or until thoroughly cooked.
Cook the spaghetti according to package instructions. Drain and keep warm.
Divide the spaghetti between the serving plates and top with the sauce and a sprinkle of Parmesan Cheese.