Bring the water with the oil and salt to the boil in a heavy-based saucepan.
Add the spaghetti and cook for 15 - 20 minutes or until cooked, but still firm.
Drain and toss extra olive oil through the spaghetti.
Meanwhile, prepare the Bolognaise sauce.
Heat the butter and oil together in a heavy-based saucepan.
Add the mince and fry until meat turns colour.
Add the Napoletana sauce and carrots and allow to simmer covered for 50 - 60 minutes.
Season to taste.
Divide the spaghetti between 4 pasta bowls.
Spoon the Bolognaise sauce on top and sprinkle pecorino shavings over.