Slice the beef thinly against the grain—this breaks up the muscle fibers for maximum tenderness. Add the soy sauce, cornstarch, black pepper, and baking soda. Mix well to coat each piece and let it sit for at least 10–15 minutes. This quick marinade tenderizes the meat and sets the base for rich flavor.

In a small bowl, whisk together oyster sauce, soy sauce, water, cornstarch, brown sugar, and black pepper. This stir fry sauce will create that glossy, savory coating that defines a great beef and broccoli dish. Set aside.

In a large skillet or wok, heat 1–2 tablespoons of oil over medium-high heat. Once hot, add the marinated beef in a single layer. Use a spoon or tongs to quickly separate the pieces so they cook evenly. Sear for 2–3 minutes per side, or until just browned and cooked through. Remove the beef from the pan and set aside.

Bring a pot of water to a boil and blanch the broccoli for exactly 2 minutes. This step keeps it vibrant green and crisp-tender. Drain and set aside. Alternatively, steam the broccoli in a steamer basket until just firm.

Reduce the pan heat to medium and add a touch more oil if needed. Add the minced garlic and stir-fry for about 30 seconds to 1 minute, until lightly golden and fragrant. Be careful not to burn it.

Pour the pre-mixed sauce into the pan with the garlic. Stir continuously as it comes to a simmer and begins to thicken. This will take about 2–3 minutes.

Add the cooked beef and broccoli back into the pan. Stir well to coat everything in the glossy, thickened sauce. Let it heat through for a minute or two. Serve hot over steamed white rice, brown rice, or noodles.