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 tamari, toasted sesame oil, honey, minced fresh ginger, and minced garlic to create the stir-fry glaze.
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 2-3 minutes until browned and caramelized on the edges, 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 until they are bright green and tender-crisp.
Return the beef to the pan, pour the sesame-ginger glaze over the top, and toss everything together for 1 minute until the sauce thickens and coats every piece.
Remove from heat and garnish with sesame seeds before serving hot.