Cut the beef into bite-sized cubes and prep all vegetables and aromatics.
In a bowl, mix oyster sauce, soy sauce, fish sauce, dark soy sauce, sugar, garlic, coconut oil, and pepper. Add beef and marinate for at least 20 minutes.
While marinating, steam rice or prep a simple salad with vegetables of your choice. I used lettuce, cherry tomatoes, cucumber, and red onion.
Heat oil in a large stainless steel or cast iron pan over medium-high heat until smoking hot.
Add the prepped vegetables and shake the pan to coat them in oil. Sauté briefly, just until they soften slightly.
Add the beef and sear, shaking the pan to brown all sides. Shake and cook until the beef is browned and the veggies are tender-crisp.
Serve hot with rice or your prepared salad. Spoon any remaining sauce in the pan over the top and enjoy!