Slice the flank steak against the grain into very thin strips and place in a glass bowl.
In a small jar, whisk together the tamari, toasted sesame oil, pear puree, grated fresh ginger, and minced garlic.
Pour the marinade over the beef strips, tossing well to coat, and let it marinate for at least 15 minutes.
Heat a large cast-iron skillet or wok over medium-high heat until very hot.
Add the beef to the skillet in a single layer, working in batches if necessary to avoid crowding the pan.
Sear the beef for 2-3 minutes until the edges are browned and slightly caramelized.
Toss in the broccoli florets and julienned carrots, stir-frying for another 3-4 minutes until the vegetables are tender-crisp.
Season the mixture with sea salt and black pepper.
Transfer the bulgogi to a plate and garnish with toasted sesame seeds and sliced green onions before serving.