Heat 2 tablespoons of vegetable oil in a large Dutch oven or heavy pot over medium-high heat. Season beef cubes with salt and pepper, then brown them in batches for 3-4 minutes per side. Remove and set aside.

Add remaining tablespoon of oil to the pot. Add diced onion and cook for 3-4 minutes until softened. Add minced garlic and grated ginger, cooking for another minute until fragrant.

Return the browned beef to the pot. Add beef broth, tomato sauce, soy sauce, and brown sugar. Stir well to combine all ingredients. Bring the mixture to a boil.

Reduce heat to low, cover the pot, and simmer for 1 hour, stirring occasionally. The beef should become tender during this time.

Add the potato chunks and carrot pieces to the stew. Cover and continue simmering for another 30-40 minutes until the vegetables are fork-tender and the beef is very tender.

Mix cornstarch with water to create a slurry. Stir the slurry into the stew and cook uncovered for 5-10 minutes until the sauce thickens to your desired consistency.

Taste and adjust seasoning with additional salt and pepper if needed. Serve hot over steamed white rice or with crusty bread.