01 - Pat beef cubes dry with paper towels. Toss beef with flour, salt, and pepper in a large bowl until evenly coated.
02 - Heat vegetable oil in a large Dutch oven or heavy pot over medium-high heat. Brown beef on all sides in batches, being careful not to overcrowd the pot. Remove browned beef and set aside.
03 - In the same pot, add chopped onions and cook for 3 minutes until softened and translucent. Add minced garlic and cook for 1 minute until fragrant.
04 - Stir in carrots, parsnips, potatoes, and celery. Cook for 3-4 minutes, stirring occasionally, to begin developing flavor.
05 - Return browned beef to the pot. Add rinsed pearl barley, bay leaves, fresh thyme, and beef broth. Stir well to combine all ingredients. Bring the mixture to a boil.
06 - Reduce heat to low, cover with a tight-fitting lid, and simmer for 1½ hours. Stir occasionally to prevent sticking and ensure even cooking.
07 - Remove the lid and continue simmering uncovered for 30 minutes. This allows the stew to thicken naturally and flavors to meld together.
08 - Discard bay leaves. Stir in chopped fresh parsley. Taste the stew and adjust seasoning with additional salt and pepper if needed.
09 - Ladle hot stew into bowls and garnish with extra fresh parsley. Serve immediately with crusty bread.