Fry gently the chopped onion and the mince. Stir till the meat has browned
Add flour, shopped garlic and the carrot. Continue stirring.
Add the tin of tomato and tomato puree and any extra stock to keep it moist. Bring to a boil and season.
Lower heat and cover half the pan for up to an hour. Stirring occasionally.
Cook spaghetti as instructed to do on the packet.
Serve the spaghetti with the Bolognese sauce on top.