Prepare the Beef: Season the beef chunks with salt and pepper, then coat lightly with flour.
Brown the Beef: In a large pot, heat the oil over medium-high heat. Add the beef in batches and brown on all sides. Remove and set aside.
Sauté Vegetables: In the same pot, add onions, carrots, and celery. Cook until softened. Add garlic and cook for another minute.
Simmer the Stew: Return the beef to the pot. Add tomato sauce, beef broth, and soy sauce. Bring to a boil, then reduce heat to low and simmer covered for 2-3 hours until the beef is tender.
Thicken the Stew: Mix cornstarch with a little water to form a slurry. Stir into the stew and simmer for an additional 30 minutes or until thickened.
Final Seasoning: Adjust salt and pepper to taste before serving.