Set the Instant Pot to Sauté and preheat for a minute. Add the Ground Beef and cook until browned, add salt. Add the Onion and Tomato Paste then cook for a few minutes then add the Garlic and cook for another couple minutes. Add the Cremini Mushrooms and Flour then stir for another minute until the flour is cooked. Once all of the ingredients are sautéed together, add the Worcestershire Sauce and Chicken Stock to the pot.

Seal the mixture and cook on high pressure for 25 minutes. Release the pressure and stir in the Egg Noodles then seal and cook it again for 2 minutes until the noodles are cooked. Once that is finished, transfer a cup of the liquid into a blender and blend with the Sour Cream until it is smooth then pour the mixture into the pot and stir well.