Thinly slice the flank steak against the grain into bite-sized strips.
In a small bowl, whisk together the beef broth, coconut aminos, arrowroot powder, and grated ginger to create the sauce.
Heat the avocado oil in a large skillet or wok over high heat until shimmering.
Add the beef strips in a single layer and sear without moving for 2 minutes to develop a golden crust.
Flip the beef and cook for another minute, then remove from the pan and set aside.
Add the broccoli florets and a splash of water to the pan, covering with a lid for 2-3 minutes to steam-tenderize.
Remove the lid, add the minced garlic, and sauté for 30 seconds until fragrant.
Return the beef to the pan and pour in the sauce mixture.
Toss everything together for 1-2 minutes until the sauce thickens and coats the beef and broccoli.
Drizzle with toasted sesame oil before serving.