Set a 6-qt Instant Pot® to the high saute setting.Season beef with salt and pepper, to taste. Heat olive oil; working in two batches, add beef and cook until evenly browned, about 3-4 minutes; set aside.Add garlic, onion, mushrooms and thyme. Cook, stirring occasionally, until tender, about 3-4 minutes. Whisk in flour until lightly browned, about 1 minute.Stir in dry sherry, scraping any browned bits from the bottom of the pot.Stir in beef broth, Worcestershire and beef. Select manual setting; adjust pressure to high, and set time for 12 minutes. When finished cooking, quick-release pressure according to manufacturer’s directions.Stir in egg noodles. Select manual setting; adjust pressure to high, and set time for 5 additional minutes. When finished cooking, quick-release pressure according to manufacturer’s directions.Stir in sour cream; season with salt and pepper, to taste.Serve immediately, garnished with parsley, if desired.