Ingredients:
1 lb flank steak, thinly sliced against the grain
2 tablespoons soy sauce
1 tablespoon oyster sauce
1 tablespoon rice vinegar
1 tablespoon cornstarch
1 tablespoon vegetable oil
1 large onion, sliced
1 bell pepper, sliced
2 cloves garlic, minced
1 teaspoon freshly ground black pepper
½ teaspoon salt
Green onions for garnish (optional)