Slice the flank steak against the grain into thin, bite-sized strips and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, toasted sesame oil, and arrowroot powder to create the stir-fry sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the beef strips in a single layer and sear for 2 minutes until browned, then remove from the pan and set aside.
Add the broccoli florets to the same pan with a splash of water, covering for 2 minutes to steam-sauté until vibrant green.
Stir in the minced garlic and grated ginger, cooking for 30 seconds until fragrant.
Return the beef to the pan and pour in the sauce, tossing everything together for 1 minute until the glaze thickens and coats every piece.