Pat the beef stew meat dry with paper towels and season with salt and black pepper.
Heat olive oil in a large heavy-bottomed pot or Dutch oven over medium-high heat.
Add the beef stew meat in batches, making sure not to overcrowd the pot, and brown on all sides for about 5 minutes per batch. Remove browned beef and set aside.
In the same pot, add the diced onion and cook for 3-4 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Stir in the tomato paste and cook for 2 minutes to deepen the flavor.
Return the browned beef to the pot and pour in the beef broth and water. Stir to combine.
Add the dried thyme, dried rosemary, and bay leaves. Bring the mixture to a boil.
Reduce heat to low, cover, and simmer for 1 hour and 45 minutes, stirring occasionally.
Add the carrots, celery, and potatoes to the pot. Cover and continue to simmer for another 45 minutes until the vegetables and beef are tender.
In a small bowl, whisk together the all-purpose flour and cold water until smooth to make a slurry.
Stir the slurry into the stew and cook uncovered for 5-10 minutes until the stew thickens.
Remove bay leaves and adjust seasoning with salt and black pepper as needed.
Serve hot, garnished with chopped fresh parsley.