Turn a slow cooker to low and coat it with cooking spray.
Heat the oil and butter in a saute pan or skillet over medium heat. Add the mushrooms and garlic. Increase the heat, cooking them until all the liquid is evaporated and the mushrooms are browned, working in batches if necessary. Add the vegetable broth and cook until the liquid is somewhat reduced. Set aside to cool slightly.
Place the chicken, mushroom soup, cream cheese, dressing mix, black pepper and the mushroom mixture in the slow cooker and stir lightly to disperse the ingredients. Cover and cook all day, about 8 hours.
Just before serving: Cook the pasta according to the package directions.
Serve the chicken with the pasta and garnish with the Parmesan and parsley.