Add beef, onion, garlic and mushrooms into the base of the pressure cooker.
In a small bowl, combine the broth, mustard, Worcestershire sauce, salt, pepper, thyme, and cornstarch in small bowl and Pour over the beef mixture.
Seal and microwave on high power 20-25 minutes.
Remove from microwave and allow pressure to release naturally until pressure indicator fully lowers, about 10–15 minutes.
Stir in the cream cheese until dissolved. Stir in the sour cream and chopped fresh parsley.
Serve over hot egg noodles.