In a large pot, combine the beef cubes and water. Bring to a boil, then reduce the heat to low. Simmer for 1-1.5 hours or until the beef is tender. Skim off any scum that rises to the top. Set the beef aside, and reserve 2 cups of the broth.

In a large pan, heat the cooking oil over medium heat. Add the garlic and onion, sautéing for 2-3 minutes until fragrant.

Add the cooked beef cubes to the pan and sauté for 3-4 minutes until slightly browned.

Stir in the soy sauce, oyster sauce, sugar, and ground black pepper. Mix well to coat the beef.

Add the reserved beef broth, star anise, and beef bouillon cube. Bring the mixture to a simmer and cook for 15-20 minutes, allowing the sauce to thicken slightly. Adjust seasoning with salt if needed.

Serve the beef pares hot over steamed rice with a side of the reserved broth. Garnish with chopped green onions if desired.