01 - Pat beef cubes completely dry with paper towels. Toss beef in a large bowl with flour, salt, and black pepper until evenly coated.
02 - Heat vegetable oil in a large Dutch oven or heavy pot over medium-high heat. Add beef in batches, browning on all sides for 4-5 minutes per batch. Transfer browned beef to a plate and set aside.
03 - Reduce heat to medium. Add chopped onions to the pot and cook for 3 minutes until softened and translucent. Add minced garlic and cook for 1 minute until fragrant, stirring constantly to prevent burning.
04 - Stir in sliced carrots, parsnips, potato chunks, and sliced celery. Cook for 3-4 minutes, stirring occasionally, until vegetables begin to soften slightly.
05 - Return browned beef to the pot. Add rinsed pearl barley, bay leaves, thyme leaves, and beef broth. Increase heat to high and bring to a rolling boil.
06 - Reduce heat to low, cover tightly with lid, and simmer for 1 hour 30 minutes. Stir gently every 20-25 minutes to prevent sticking and ensure even cooking.
07 - Remove lid and continue simmering uncovered for 30 minutes. This allows the broth to reduce and thicken naturally while flavors concentrate.
08 - Discard bay leaves. Stir in chopped fresh parsley. Taste and adjust seasoning with additional salt and pepper if needed.
09 - Ladle hot stew into bowls. Garnish with additional fresh parsley and serve immediately while steaming hot.