Note: I like to add chopped yellow or sweet onion instead of the scallions, because I usually have a onion on-hand. I just add the chopped onion to the skillet with the broccoli.

Cut the steak into 2-inch-wide strips with the grain, then slice across the grain into 1/8-inch-thick slices. (You can use skirt, hanger, or flatiron steaks as a substitute for flank. I have also used top round.)

In a medium bowl, combine beef and soy sauce. Cover with plastic wrap and refrigerate at least 10 mins or up to 1 hr. Meanwhile, whisk the sauce ingredients together in a liquid measuring cup or small bowl. In another small bowl, combine garlic, ginger, and 1 tsp peanut oil. Set aside.

Heat 1-2 tsp peanut oil in 12-in nonstick skillet over medium-high heat, until hot and rippling. Add half of beef to skillet and break up clumps; cook, without stirring, for 1 minute, then stir and cook until beef is browned around edges and cooked through, about 1-2 mins. Don’t overcook the meat – cook until just barely cooked through so meat stays tender. Transfer beef to a medium bowl and cover with a lid and foil. Heat another 1-2 tsp peanut oil in the skillet and repeat with remaining beef.

Add 1 Tbsp peanut oil to now-empty skillet; heat until rippling and hot. Add broccoli and cook 30 seconds; add water, cover pan, and reduce heat to medium. Steam broccoli until tender-crisp, about 2 mins. Push broccoli to the sides of skillet and add garlic/ginger mixture. Cook, mashing the mixture with a spoon, until fragrant, about 15-30 secs. Stir mixture into broccoli. Add beef back to skillet and toss to combine. Whisk the sauce to recombine, and add to skillet. Cook, stirring constantly, until sauce is thickened and evenly distributed, about 1-2 mins. Sprinkle with scallions, and serve with rice, if desired.