Pat the beef dry with paper towels and season with salt, pepper, and paprika.
(Optional but recommended) Heat a tablespoon of oil in a large skillet over medium-high heat. Brown the beef in batches for 2–3 minutes per side, then transfer to the slow cooker.
Add the potatoes, carrots, celery, onion, and garlic to the slow cooker.
In a bowl, whisk together the beef broth, tomato paste, Worcestershire sauce, thyme, and rosemary.
Pour the broth mixture over the beef and vegetables.
Add the bay leaves and gently stir everything together.
Cover and cook on LOW for 8–9 hours or HIGH for 4–5 hours, until the beef is fork-tender and the vegetables are cooked through.
About 20 minutes before serving, mix the cornstarch and cold water until smooth.
Stir the slurry into the slow cooker and continue cooking until the broth thickens.
Remove the bay leaves.
Taste and adjust seasoning if needed.
Garnish with fresh parsley or thyme and serve hot with crusty bread or biscuits.