Blanch broccoli in boiling water for 2–3 minutes until bright green. Drain, rinse with cold water, and pat dry.
Slice the flank steak thinly and season with black pepper.
In a bowl, mix soy sauce, water, sugar, garlic, ginger, and cornstarch.
Heat half the sesame oil in a skillet over high heat. Cook beef until just done, then remove.
Add remaining oil and cook broccoli for 1–2 minutes.
Return beef to the pan, pour in sauce, and cook until thickened.
Serve Healthy Beef and Broccoli immediately.