In a large mixing bowl, combine the beef broth, tomato paste, flour, 1/2 teaspoon salt and 1/4 teaspoon pepper. Mix well until all ingredients are well combined and set aside.
In a large fry pan over medium-high heat, add one tablespoon avocado oil and the beef. Season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Brown the pieces of beef on all sides (about 1-2 minutes per side).
Pour the beef into the slow cooker and top with the onions, garlic, carrots, celery, and potatoes.
Pour the beef broth mixture in the slow cooker and top with the sprigs of thyme and bay leaves.
Place the lid on the slow cooker and cook on LOW for 8 hours, or until the meat and veggies are fork tender.
When the cooking time is up, discard the thyme and bay leaves. Serve the stew over egg noodles or in bread bowls. Enjoy!