Sear hard the beef in pressure cooker with oil, remove beef and add the onion, celery, carrots and mushrooms. Cook, stirring frequently, until the onions are translucent and the mushrooms have given off some of their liquid, 3-4 minutes, then add the wine if using and cook down until half the wine is gone. Add the thyme, tomato paste, Worcestershire sauce and black pepper. Stir until the mixture is fragrant (1-2 minutes). Add the barley and liquid, and the beef with its resting juices.
Lock the lid in place. Set the pressure cooker for High Pressure for 12 minutes. When time is done use the Natural Pressure Release method, which will release the pressure in approximately 7 to 10 minutes.
When the pressure is released, pour the soup into individual serving bowls, and serve hot with a quick Microplane of parmesan, lemon zest and a dollop of sour cream
Or, pack into freezer-safe containers. Let the soup cool completely before freezing.
Adapted for the Pressure Cooker by Chef Xav