For the Marinade • Beef sirloin – 1 and 1 half pounds, thinly sliced against the grain for tenderness. • Soy sauce – 2 tablespoons, adding a rich umami flavor to the meat. • Oyster sauce – 1 tablespoon, enhancing the savory depth of the marinade. • Cornstarch – 1 tablespoon, helping to tenderize the beef while thickening the sauce. • Sesame oil – 1 teaspoon, infusing a nutty aroma into the marinade. • Black pepper – 1 quarter teaspoon, elevating the flavor profile with a subtle kick. For the Stir Fry Sauce • Soy sauce – 3 tablespoons, reinforcing the savory foundation of the dish. • Oyster sauce – 2 tablespoons, for a robust layer of flavor. • Dark soy sauce – 1 tablespoon, adding color and a deeper flavor. • Brown sugar – 1 tablespoon, balancing out the savory flavors with a hint of sweetness. • Beef broth – 1 half cup, providing richness to the stir fry sauce. • Cornstarch – 1 tablespoon (for the sauce), thickening the stir fry to a perfect consistency. • Cold water – 2 tablespoons, ...