Cut beef into 1-inch cubes. Peel and slice carrots and potatoes. Chop celery and onion, and mince garlic. Have all ingredients ready before you begin.

Place beef cubes in a bowl and sprinkle with flour. Toss to coat evenly; this helps thicken the stew as it cooks.

Heat olive oil in a skillet over medium-high heat. Brown beef in batches to avoid overcrowding, searing all sides until deep golden. Transfer browned beef to the crockpot.

With the skillet hot, add a splash of beef broth and scrape up browned bits. Pour the deglazed liquid over the beef in the crockpot to capture extra flavor.

Place potatoes and carrots at the bottom of the crockpot, then add sliced celery and chopped onions on top. Proper layering ensures even cooking of the vegetables.

Sprinkle garlic, thyme, salt, and pepper over the ingredients. Mix beef broth, tomato paste, and Worcestershire sauce in a bowl and pour evenly over the crockpot contents, ensuring ingredients are submerged.

Cover the crockpot and set to low. Allow the stew to cook for 8 hours, checking occasionally to ensure a gentle simmer. The stew is ready when the beef is tender and flavors are well blended.

Taste and adjust seasoning if needed. Ladle into bowls with plenty of vegetables and beef, garnish with fresh parsley, and serve hot with crusty bread if desired.