Start by trimming and thinly slicing your lean flank steak against the grain. Chop the baby bok choy, including both stalks and leaves. Slice the red bell pepper into strips.

In a large non-stick skillet or wok, heat over medium-high heat for about 2 minutes. Coat with cooking spray or sesame oil to prevent sticking.

Add the sliced flank steak to the hot skillet. Cook for about 3-4 minutes, stirring occasionally, until the beef is browned.

Once the beef is browned, stir in the minced garlic and freshly grated ginger, cooking for an additional 30 seconds.

Next, toss in the sliced red bell pepper and chopped bok choy. Stir-fry for about 3-4 minutes, until the vegetables are tender but still crisp.

In a small bowl, whisk together low-sodium soy sauce, rice vinegar, sesame oil, cornstarch, and a splash of water until smooth. Pour this sauce into the skillet.

If desired, stir in hoisin sauce and a dash of sriracha. Cook for another 1-2 minutes until flavors meld.

Spoon your Bok Choy Stir-Fried Beef onto plates and garnish with chopped green onions and sesame seeds. Serve hot.