In a 6-quart slow cooker, stir together Beef Stock (4 cup), Onion (1 1/2 cup), Barley (1 cup), Water (1 cup), Celery (1 cup), Kosher Salt (1 teaspoon), Freshly Ground Black Pepper (1/2 teaspoon), and Garlic (6 clove).
Add Fresh Thyme (4 sprig) and Bay Leaf (3), then dollop Tomato Paste (1/4 cup) on top.
Heat the Olive Oil (1 tablespoon) in a large skillet over medium-high. Add the Beef Chuck (1 pound) and cook until well-browned, about 6 minutes, turning once. Add the first batch of browned beef cubes to the slow cooker.
Repeat with the remaining Olive Oil (1 tablespoon) and Beef Chuck (1 pound). Scatter the Carrot (2 1/2 cup) over the beef.
Cover and cook on low until meat and grains are tender, about 8 hours.
Discard the thyme sprigs and bay leaves. Ladle the stew into 8 bowls, then sprinkle with Fresh Parsley (to taste). Serve and enjoy!