Slice the flank steak against the grain into very thin, bite-sized strips to ensure maximum tenderness.
Heat the toasted sesame oil in a large stainless steel skillet or wok over medium-high heat until shimmering.
Add the beef strips to the pan in a single layer and season evenly with sea salt, black pepper, garlic powder, and ground ginger.
Sear the beef for 3 minutes without moving it to develop a golden crust, then toss and cook for 1 additional minute before removing the meat from the pan.
In the same pan, add the broccoli florets and one tablespoon of water, then immediately cover with a lid to steam for 2 minutes until tender-crisp and vibrant green.
Remove the lid and return the beef to the pan, pouring the tamari over the mixture.
Toss everything together for 60 seconds until the sauce reduces slightly and glazes the beef and broccoli.
Transfer to a plate and garnish with sesame seeds for a clean, protein-packed meal.