Clean and trim fat from the steak. Slice the steak against the grain. Place the steak in a bowl. Add cornstarch, baking soda and mix well.
In the slow cooker: add soy sauce, dark soy sauce, brown sugar, shaoxing wine, oil, garlic and mix. Add beef and mix until uniformly coated.
Slow cook on high for 2 ½ - 3 hours (cook on low for 5-6 hours) or until the meat is tender.
Remove the lid and mix the beef until well coated with the sauce. Add green onions then mix again. Cover with the lid for 3 minutes or until the green onions have slightly wilted. Season with salt if needed.
Garnish with sesame seeds. Serve with rice or vegetables. Enjoy!