Begin by slicing your flank steak into thin strips against the grain for maximum tenderness. In a bowl, toss the beef with soy sauce, black pepper, and cornstarch. Let it marinate for 15 to 30 minutes at room temperature.

While the beef is marinating, whisk together the soy sauce, chicken or veggie broth, honey, toasted sesame oil, minced garlic, grated fresh ginger, and a pinch of cornstarch until well combined in a separate bowl.

Heat a large skillet or wok over medium-high heat and add vegetable oil. Cook the marinated beef in batches for about 2 to 3 minutes until golden brown.

In the same skillet, add sliced onions, bell peppers, and carrots. Sauté for approximately 3 to 4 minutes until the onions become translucent.

Next, stir in the broccoli and continue cooking for about 2 minutes until crisp-tender.

Return the cooked beef to the skillet along with any juices. Pour the sauce over the beef and veggies, stirring gently to combine and cook for an additional 2 minutes.

Toss in chopped scallions and garnish with sesame seeds if desired. Serve immediately over rice or quinoa.