Mix the meat with the breadcrumbs, grated onion and
carrot. Season well, then mix with the egg to bind.
Shape into 16 balls. Brown on all sides in the hot
oil. Remove from the pan with a draining spoon.
Drain on kitchen paper.
Meanwhile, cook the pasta
according to the packet directions. Drain and place
in a casserole (Dutch oven).
Arrange the meatballs
on top. Fry (sauté) the chopped onion and mushrooms,
stirring, in the meatball pan for 2 minutes.
Stir in
the flour and cook for 1 minute. Remove from the
heat and blend in the stock and tomato puree. Bring
to the boil, stirring. Pour over the meatballs.
Sprinkle with the oregano and a little salt and
pepper. Cover and cook in the oven at
180°C/350°F/gas mark 4 for 30 minutes.