This meal might just rival your favorite take-out version and is quite easy to prepare. All of the prep work--from chopping the veggies to mixing the sauce and the marinade--can be done well in advance so that the actual cooking process takes mere minutes.Freeze the flank steak for 15 to 20 minutes for easier slicing. Although rice is traditional for serving, noodles are a great option. We sometimes enjoy this with black bean pasta that is unexpectedly delicious...even the kids think so.
Whisk together the marinade ingredients. Add the beef, toss to coat, and refrigerate for 1 hour. This can be done in a bowl or a zip-top bag.
Mix together the sauce ingredients. If desired, this can be done earlier in the day and refrigerated.
Heat 1 tablespoon oil in a 12-inch nonstick skillet or wok set over medium-high heat. Stir-fry the beef until it reaches a point just a shade below your preferred degree of doneness. (I like to see a little pink in the center at this point.) Remove to a plate.
Add the remaining tablespoon of oil followed by the garlic, ginger, and pinch of salt and sugar; stir-fry 30 seconds.
Add the onion and cook until beginning to soften, about 2 minutes. Stir in the broccoli and cook until crisp-tender, about 4 to 5 minutes.
Return the beef to the pan, add the sauce*, and cook, stirring to make sure everything is evenly coated, until the sauce is thickened, about 2 to 3 minutes.
Serve over rice or toss with noodles, and sprinkle with desired garnishes.
Notes
If you mixed the sauce ingredients ahead of time, make sure to stir to reincorporate all the ingredients before adding to the pan.