Love this recipe! This is my go-to on busy nights. I'd never tried bok choy before and was really impressed - love the crunch! I've even made it without the beef - using 20-30 shrimp (unchopped) and really enjoy it. I do add garlic (I love garlic!) and I have used a chilli-garlic sauce instead of the oyster-flavored sauce and sesame oil for the canola oil. I also add some shitake mushrooms based on other comments I saw. Always very good!