In a bowl, mix soy sauce, garlic clove, grated ginger, and sesame oil. Coat the beef with this marinade and let it soak for 30 minutes.
Combine cornstarch, water, soy sauce, rice vinegar, honey, and freshly ground black pepper in a bowl. Stir until well-mixed.
Heat vegetable oil in a wok or large skillet. When the oil is hot, add the marinated beef. Cook for about 5 minutes until it's nicely browned. Remove from the wok and set aside.
In the same wok, toss in sliced onion, red bell pepper, green beans, and champignons. Stir-fry until the veggies are tender yet still crispy.
Put the cooked beef back into the wok with the veggies.
Drizzle the black pepper sauce over the beef and veggies. Stir well to coat everything evenly.
Spoon the savory Black Pepper Beef stir-fry over steamed rice or your preferred noodles.