In a bowl, toss the beef with all the marinade stuff. Doesn’t need to be perfect—just make sure the beef gets coated. Let it sit for a while. If you’ve got 30 minutes, great. Do some chores first or play with your dog (if you have one).
Grab another bowl and whisk everything together. Cornstarch is your friend here—it thickens the sauce like magic.
Boil water. Add broccoli. Let it cook for about a minute, then drain and rinse under cold water to keep it bright and hydrated.
Get a pan hot, splash in some oil, and toss in the garlic. Stir quickly. Add beef, spread it out, don’t crowd it. Brown it up for a few minutes. Pour in the sauce and broccoli. Stir things around until the sauce thickens and everything is coated in that sticky goodness.
Spoon it over rice or slurp it up with noodles. Sprinkle sesame seeds on top if you’ve got 'em. Or not. No rules here.