Cook the penne pasta according to package directions. Drain and set aside.

Over medium heat, carmelize the onion in 2 Tablespoons of olive oil. Sprinkle the onion with a little salt, and cook the onions until they are a nice brown color and taste sweet. The onions will have a "gooey" texture and excess liquid will be evaporated.

Add the chicken, mushrooms and garlic to the onions. Add a little more oil if necessary. Saute until chicken is cooked through and the mushrooms are soft. Remove from skillet and set aside.

Add wine to the skillet. Bring to a slow boil and reduce by 2/3 until the alcohol smell has cooked out.

Lower heat and once the mixture is no longer boiling, add the sour cream and heavy cream. Stir constantly until melted. Swirl in the butter. Add cooked chicken mixture and stir.

Toss with the cooked and drained pasta. Good served with coarsely grated parmesan cheese.