Slice the beef against the grain into 0.5 cm (1/4 inch) thick slices or 1-cm (1/2 inch) sticks. Transfer to a small bowl. Add soy sauce, peanut oil, and cornstarch (*Footnote 1). Gently mix well by hand until all the slices are coated with a thin layer of sauce. Marinate for 10 minutes while preparing the other ingredients.

Combine all the ingredients for the sauce in a medium-sized bowl. Mix well.

Add 1/4 cup water into a large nonstick skillet over medium-high heat until the water begins to boil. Add the broccoli and cover. Steam until the broccoli just turns tender and the water evaporates,1 minute or so. Transfer broccoli to a plate. Wipe the pan with a paper towel held in a pair of tongs if there’s any water left.

Add the oil and swirl to coat the bottom. Heat over medium high heat until hot. Spread the steak in a single layer. Allow to cook without touching for 30 seconds, or until the bottom side is browned. Flip to cook the other side for a few seconds. Stir and cook until the surface is lightly charred and the inside is still pink.

Add the garlic and ginger. Stir a few times to release the flavor and fragrance.

Return the broccoli to the pan. Stir the sauce again to dissolve the cornstarch completely and pour it into the skillet. Cook and stir until the sauce thickens, about 1 minute. Transfer everything to a plate immediately. Serve hot as a main dish.