01 - Rinse the rice thoroughly, then combine with 500ml (2 cups) water in a saucepan. Bring to a boil, reduce heat to low, cover, and simmer for 15 minutes. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork before serving.
02 - While the rice cooks, in a medium bowl, combine sliced beef with 2 tablespoons soy sauce, 1 tablespoon oyster sauce, 1 teaspoon cornstarch, 1 teaspoon sesame oil, and 1 teaspoon sugar. Mix well and let marinate for at least 10 minutes.
03 - In a small bowl, whisk together all sauce ingredients: 2 tablespoons soy sauce, 1 tablespoon oyster sauce, 1 tablespoon hoisin sauce, 1 tablespoon rice vinegar, 1 teaspoon brown sugar, 1 teaspoon cornstarch, and 2 tablespoons water. Set aside.
04 - Heat 1 tablespoon vegetable oil in a large skillet or wok over medium-high heat. Add marinated beef in a single layer and sear for 1-2 minutes per side until just browned. Remove beef to a plate.
05 - Add the remaining 1 tablespoon oil to the skillet. Stir-fry broccoli florets for 3-4 minutes until bright green and just tender. Add minced garlic and ginger; stir-fry for 1 minute until fragrant.
06 - Return beef to the pan. Pour in the prepared sauce and toss everything together. Cook for 2-3 minutes, stirring, until the sauce thickens and coats the beef and broccoli.
07 - To serve, divide the cooked rice among four bowls. Top with the beef and broccoli mixture. Garnish with sliced green onions and toasted sesame seeds, if desired.