Preheat oven to 400 degrees.

Using the pot you used to cook your pasta, reheat the pot over high heat and add olive oil.  Once the oil is hot, add mushrooms and cook until they are beginning to brown and are glistening.

Reduce the heat to medium high and add onions, salt and pepper.  Sauce the mushrooms, onions and salt and pepper until the liquid produced from the mushrooms has evaporated.

At this point, add in the Marsala wine and cook the mixture for about 3 minutes, or until almost evaporated.

Add the butter and stir until melted.  Add in the flour and stir until the flour has been absorbed.  Add the chicken stock, a little at a time.  Make sure to stir the whole time with a wooden spoon.  Ensure after each addition of stock, that it has been fully absorbed into the butter, flour, mushroom mixture.

After adding in all of the stock, let the mixture simmer together for 2 minutes, stirring frequently.  Once the sauce has thickened, remove the pan from the heat.

If you're using a large enough pan or an oven safe dish, add in the cooked pasta and stir until combined.  If not, pour the mushroom/broth/flour mixture into a 2 quart baking dish and stir in half of the shredded parmesan and all of the mozzarella cubes.  Stir in 2 tablespoons of the parsley until all ingredients are evenly mixed.

Bake for 25-30 minutes (until the top pasta pieces are slightly browned and a bit crispy).  Sprinkle with the reserved parsley and parmesan cheese.

Enjoy!!