01 - Combine 1 tablespoon soy sauce, 1 tablespoon cornstarch, and 1/2 tablespoon grated ginger in a bowl. Add the sliced beef, toss to coat thoroughly, and let marinate for 10 minutes at room temperature.
02 - Whisk together the remaining soy sauce (2 tablespoons), oyster sauce, rice vinegar, brown sugar, remaining ginger (1/2 tablespoon), water, and black pepper in a separate bowl until the sugar dissolves completely.
03 - Heat 1 tablespoon vegetable oil in a large wok or skillet over high heat until smoking. Add the marinated beef in a single layer and stir fry for 2-3 minutes until browned on the edges but still pink in the center. Remove beef and set aside on a plate.
04 - Add the remaining oil to the hot pan. Toss in broccoli, onion, carrot, and garlic. Stir fry over high heat for 3-4 minutes until vegetables are bright green and tender-crisp.
05 - Return the beef to the pan. Pour in the prepared sauce and stir constantly to coat everything. Cook for 2-3 minutes until the sauce bubbles and thickens enough to cling to the meat and vegetables.
06 - Remove from heat and drizzle with sesame oil. Toss well to distribute the aroma. Serve immediately over steamed jasmine or brown rice.