Set the instant to sauté mode at medium heat then add the olive oil and heat until shimmering.

Add half of the beef, salt, and pepper and stir then let it cook for 3-4 minutes or until the beef starts to get some color on it. (The beef won’t be cooked through completely, we just want to get a nice sear at this point.)

Remove the beef then add the remaining beef and cook until brown then set aside.

Drain out any liquid and wipe the pot out then melt the butter and add the onion.

Cook until it starts to soften then add the mushrooms and garlic and cook until they soften and caramelize.

Stir in the flour then add the beef broth, mustard, and Worcestershire sauce and let it boil.

Carefully use a spoon to push the quick-release steam knob on top and let all the steam out then take the lid off.

Add the pasta but do not stir, simply push the pasta down below the water level then cover and seal with the lid.

Set it to manual and cook for 2 minutes then carefully push the quick-release knob on top, remove the lid, and stir.

Pour the sour cream into a medium bowl then stir in 2 tablespoons of the beef liquid from the pot at a time until it has a drizzly consistency. (This is to temper the sour cream so it doesn’t separate when you add it to the pot.)

Pour the sour cream into the pot and stir to combine then serve with freshly minced parsley for garnish if desired.