Slice the flank steak against the grain into thin strips and season with sea salt and black pepper.
In a small bowl, whisk together the tamari, honey, and grated fresh ginger to create the stir-fry sauce.
Heat the sesame 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 2-3 minutes until browned and tender.
Remove the beef from the pan and set aside, then add the broccoli florets and sliced red bell peppers to the same pan.
Sauté the vegetables for 4-5 minutes with a splash of water until they reach a vibrant green and crisp-tender texture.
Stir in the minced garlic and cook for 30 seconds until fragrant, then return the beef to the pan.
Pour the prepared sauce over the beef and vegetables, tossing constantly for 1 minute until the glaze thickens and coats everything.
Garnish with toasted sesame seeds before serving hot.