Set Instant Pot to high saute setting. Cut stew meat into cubes. Season with kosher salt and pepper, to taste. Cook for about 3-4 minutes until browned. Set aside.
Combine garlic, onion, mushrooms and thyme. Cook until tender for 4 minutes. Whisk in flour for about 1 minute.
Add vanilla, beef broth and Worcestershire sauce. Return stew meat to pressure cooker. Select Manual setting, adjust pressure to high and set time 12 minutes. Make sure spout is set to "Sealed". After finished, do a Quick-Release according to maufacturer's directions.
Stir in egg noodles. Close pressure cooker again. Select Manual setting, adjust pressure to high and set time for 5 additional minutes. Adjust the spout to "Sealed". After done, Quick-Release.
Add sour cream, season with salt and pepper, to taste.
Serve immediately, garnish with parsley, if desired.