Prepare the sauce: In a small bowl, whisk together the soy sauce, oyster sauce, cornflour, brown sugar, and beef stock. Stir until the cornflour is fully dissolved and the liquid looks smooth and dark brown. Set aside.

Blanch the broccoli: Bring a small pot of water to a rolling boil. Add the broccoli florets and cook for 60 seconds only. You will see the broccoli turn a bright, vivid green and the stems become slightly tender. Drain immediately and run under cold water to stop the cooking. This keeps the broccoli crunchy and vibrant.

Brown the beef: Heat 1 tablespoon of oil in a large frying pan or wok over high heat until it shimmers and you see a faint wisp of smoke. Add half the beef strips in a single layer. Let them sear undisturbed for 60 seconds — you should hear a loud sizzle. Flip them and cook for another 30 seconds. The beef should be browned on the outside but still pink inside. Transfer to a plate and repeat with the remaining oil and beef.

Cook the aromatics: Reduce the heat to medium. Add the minced garlic and grated ginger to the pan. Stir constantly for 30 seconds. The smell will become fragrant and slightly sweet. Be careful not to let them burn.

Combine everything: Return the beef and any juices from the plate to the pan. Add the blanched broccoli. Pour the sauce over everything. Stir well to coat all the ingredients. The sauce will immediately start to bubble and thicken. Cook for 2 minutes, stirring often, until the sauce clings to the beef and broccoli and looks glossy and thick.

Finish and serve: Turn off the heat. Taste the sauce and adjust seasoning if needed. Serve immediately over steamed rice or noodles. The sauce should be thick enough to coat the back of a spoon.