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 to the beef. Mix well by hand until all slices are coated. Marinate for 10 minutes while preparing other ingredients.

In a medium-sized bowl, combine all the ingredients for the sauce. Mix well.

Heat 1/4 cup water in a large nonstick skillet over medium-high heat until boiling. Add the broccoli and cover. Steam until the broccoli becomes tender, about 1 minute.

Transfer the broccoli to a plate. Wipe the pan with a paper towel if there’s any leftover water.

Add peanut oil to the skillet and heat over medium-high heat. Spread the steak in a single layer. Cook without touching for 30 seconds until the bottom side is browned. Flip and cook the other side for a few seconds.

Stir until the steak is lightly charred and still pink inside.

Add garlic and ginger to the skillet. Stir to release the flavor.

Return the broccoli to the pan. Stir the sauce to dissolve the cornstarch completely, then 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.