Cook pasta according to package directions. Reserve about 1 cup pasta cooking water, then drain pasta.
Meanwhile, slice chicken into thin, bite size slices.
In a large skillet over medium high heat, heat 1 tablespoon oil. Add chicken breasts, stirring to cook through and brown. Remove from the pan and set aside.
Add remaining oil and mushrooms to skillet. Cook for about 5 minutes, until softened. Add Boursin and ½ cup cream. Add parmesan and pepper and stir until melted. Return chicken to skillet. Stir to coat, adding remaining cream as needed.
Add pasta to skillet and toss to combine. Add pasta cooking water as needed to reach desired consistency. Add salt to taste.
Serve and garnish with parsley.
Notes
Leftovers will keep in an airtight container in the refrigerator for up to 3 days.
Leftovers can also be frozen but the pasta will not have the same consistency.