Slice 1 lb beef flank steak thinly against the grain
Mix 1/4 cup soy sauce, 2 tablespoons oyster sauce, 1 tablespoon cornstarch, 1 tablespoon water, 1 tablespoon brown sugar, 2 cloves minced garlic, and 1 teaspoon grated ginger
Marinate the beef in half of the sauce for 15 to 30 minutes
Cut 3 cups broccoli into florets
Heat 1 tablespoon oil in a skillet or wok over medium-high heat
Cook the beef in a single layer until browned, then remove it from the pan
Add another 1 tablespoon oil to the pan
Add the broccoli and 1/4 cup water, then cover and steam for 2 to 3 minutes
Uncover and stir until the broccoli is tender-crisp
Return the beef to the pan
Add the remaining sauce and stir until everything is coated and the sauce thickens
Serve hot over rice or noodles