Slice the top sirloin steak into very thin strips against the grain and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, toasted sesame oil, minced garlic, grated fresh ginger, arrowroot powder, and water 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 to the hot pan in a single layer and sear for 1-2 minutes until browned, then remove the beef from the pan and set aside.
Add the broccoli florets to the same pan with a splash of water, cover with a lid for 2 minutes to steam until tender-crisp and bright green.
Return the beef to the pan and pour the prepared sauce over the mixture.
Toss everything together for 1 minute until the sauce thickens and coats the beef and broccoli beautifully.
Garnish with sesame seeds before serving warm.