Slice the steak into thin strips. In a medium bowl combine oyster sauce, soy sauce, ¼ teaspoon black pepper, sugar, wine, cornstarch and sesame oil. Mix well.

Add about 1 tablespoons of vegetable oil in a large skillet or wok over medium-high heat. Add the beef strips and stir-fry about 3 minutes. Remove from the pan. Add garlic and stir fry for 15 seconds. Add peppers and onions and stir-fry until slightly soft. Return the beef strips back into the pan. Pour in the sauce mixture. Simmer until the sauce has thickened. Sprinkle with ½ teaspoon of ground black pepper.