Heat skillet with oil, over medium to medium-high heat, until shimmers or a drop of water flicked in it dances.
Add beef and stir until beef is browned on all sides. Add pepper, onion powder and tomato paste. Stir until blended. Add to slow cooker.
Add onions, carrots, potatoes, celery, brown sugar, Worcestershire sauce, soy sauce, beef broth, ginger root, garlic, bay leaves, salt and vinegar.
Stir until combined and coated.
Cover and cook on low until beef is tender, 6-8 hours, or high 3-4 hours.
In bowl whisk together flour, butter, and water, beef broth or stew liquid until smooth and creamy.
Add into slow cooker and gently combine. Cover and cook on high for 15 minutes or until thickened.
Discard bay leaves and adjust seasonings as desired.
Serve on its own, or omit potatoes and serve over rice or egg noodles with a dollop of sour cream or greek yogurt, if desired.