In a large pan, melt butter at medium heat. Brown breasts for 1 minute on each side. Transfer the breasts in a plate.
In the same pan, brown mushrooms and onion for 2 to 3 minutes at medium heat. Pour white wine and reduce until there's no more liquid.
Pour in the dairy mix and parmesan. Heat until first simmering while stirring. Season. Set back breasts in the pan. Cover and cook at medium‑low heat for 10 to 12 minutes, until the flesh inside loses its pink colour.
Meanwhile, cook linguines al dente in a casserole filled with salted boiling water. Add asparagus to the casserole 3 minutes before the end of cooking. Drain. Set back into the casserole and add olive oil. Pepper and stir.
Serve with chicken.