Turn the Instant Pot to Saute and add the oil.
1 tablespoon olive oil
Brown beef for 2 mins on all sides, in batches if needed, seasoning with salt and pepper. Remove to a plate.
2 pounds beef stew meat, Salt and pepper
Melt the butter in the pot. Add the onions and saute them for 2-3 minutes. Stir in mushrooms and cook for 2-3 more minutes until they begin to brown and release their liquid. Add garlic and saute for 30 seconds, then press cancel.
1 tablespoon butter, 1 medium onion, 1 teaspoon minced garlic, 8 ounces baby bella mushrooms
Return beef to the pot. Add flour and stir to coat. Add Worcestershire sauce and broth, scraping the brown bits from the bottom of the pot. Stir well.
3 tablespoons flour, 1 tablespoon Worcestershire sauce, 1 ½ cups beef broth
Secure and seal the lid. Cook on Manual High for 15 minutes, allowing a 5 minute natural pressure release.
Carefully remove the lid. Remove 3 tablespoons of broth from the pot and whisk it into the sour cream to temper it, then stir the mixture back into the pot.
⅓ cup sour cream
Optional: Add in the egg noodles, mix, then close your Instant Pot lid for about 10 minutes, letting them cook in the sauce on residual heat. Spoon into bowls and enjoy!
8 ounces egg noodles, uncooked