In a small bowl, toss the mushrooms with the balsamic vinegear.

Heat oil in a large, heavy skillet. Saute mushrooms, onion and garlic... browning lightly.

Add chicken, and cook until heated through.

Add chicken stock, marsala and wine.... and cook until reduced by half.

Add in cream and bring back to a boil, then turn down heat and simmer. Salt and pepper to taste, and add more marsala if needed.

In a separate pot, cook the rigatoni until al dente.

Add the cooked pasta to the chicken mixture and finish with the basil, parmesan, butter.