Slice steak against the grain into 2" pieces about ¼" thick. Place in a bowl and add baking soda, low sodium soy sauce, sesame oil, white pepper, corn starch, and avocado oil. Mix well and marinate for 20 minutes. While the steak is marinating, make the sauce.
In a small bowl, mix together oyster sauce, rice cooking wine, low sodium soy sauce, dark soy sauce, Member’s Mark™ Coarse Black Pepper, sugar, beef stock, and corn starch. Mix until the sauce is thoroughly combined. Set aside.
Heat 4 tbsp of vegetable oil in a large wok or pan over high heat. Add the beef (in batches if needed) and cook for 2-3 minutes until golden brown. Remove the beef and leave about 2 tbsp of oil in the pan.
Over medium high heat, add the minced garlic to the pan or wok and saute for 30 seconds. Add the sliced onions and bell pepper; cook for 1-2 minutes over high heat, or until the vegetables are slightly softened but still crisp.
Add the cooked beef back to the pan. Mix the sauce a final time to pick up any corn starch, then pour the sauce along the edge of the wok or pan.
Mix and toss the sauce and ingredients for another 1-2 minutes over high heat until the sauce has thickened.