Velvet the lamb: In a bowl, mix baking soda, sugar, soy sauce, and oil. Toss lamb strips in and marinate for 15 minutes.
Prepare the sauce: Whisk together soy sauce, oyster sauce, bean sauce, hoisin, sambal olek, red wine vinegar, sugar, water, five-spice, and cornstarch. Set aside.
Cook vegetables: Heat neutral oil in a wok or skillet, add garlic, ginger, shiitake mushrooms, and scallions. Stir fry until fragrant and mushrooms are tender. Remove and set aside.
Cook lamb: Add oil to the pan and stir fry marinated lamb on high heat until cooked through and slightly caramelized.
Combine: Return vegetables to the pan, pour in the sauce, and toss everything until the sauce thickens and coats the lamb and veggies evenly.
Finish: Drizzle toasted sesame oil, toss gently, and serve hot.