In a small bowl, mix the soy sauce, rice vinegar, sesame oil, grated ginger, and garlic powder to create the marinade.

Place the sliced beef in the marinade, ensuring it's evenly coated. Let it marinate while preparing the vegetables.

Heat a drizzle of oil in a large pan or wok over medium-high heat.

Add the marinated beef to the pan, cooking for a few minutes until browned on all sides. Remove from the pan and set aside.

In the same pan, add the broccoli florets, bell peppers, and snow peas. Stir-fry for a few minutes until they are crisp-tender.

Return the beef to the pan with the vegetables. Toss everything together and cook for another minute.

Season generously with salt and pepper to taste.

Sprinkle sesame seeds over the stir-fry before serving.