Spaghetti with Tuna and Marsala Sauce

Ingredients:

3 tablespoons olive oil
1/2 cup finely chopped onion
1/2 cup finely chopped carrot
1/2 cup finely chopped celery
1 large garlic clove, minced
1 pound fresh tuna, cut into 1/2-inch cubes
2 tablespoons tomato paste
1 cup dry Marsala wine
Pinch ground nutmeg
1 small bay leaf
Salt and pepper
12 ounces spaghetti

Directions:

Heat the olive oil in a medium skillet over medium heat.  Add the onion, carrots, celery, and garlic.  Saute until the vegetables are tender but not brown, about 10 minutes.  Increase the heat to medium-high and add the tuna.  Saute, stirring often, for 2 minutes.  Add the tomato paste, Marsala, nutmeg, and bay leaf to the skillet.  Stir gently to blend the tomato paste into the sauce.  Reduce the heat and simmer for 5 minutes.  Season with salt and pepper.

Meanwhile cook the pasta in boiling salted water.  Drain and reserve some of the pasta cooking water.  Add the pasta to the sauce and cook to heat through.
Add some of the reserved cooking water if the sauce is too thick.