Fry the onion and garlic in the oil until soft, then add the mince and cook until brown.
Mix through the carrot and pour in the chopped tomatoes. Add the herbs and seasoning, then reduce the heat and simmer for 45 minutes.
After 35 minutes, bring a large pan of salted water up to the boil. Add the spaghetti and cook for 10 minutes, then drain and divide between plates.
Spoon over the spaghetti bolognese and garnish with cheese and chopped parsley, if using.