Heat a wok or large frying pan on a very high heat. Add a little oil and then the beef and chilli. Cook, stirring frequently until the beef is well browned.

Add oyster / soy sauce and spinach and cook for another minute or until the spinach is just starting to wilt.

Remove from the heat. Taste season and serve with sesame seeds / tahini and sesame oil (if using) scattered / drizzled over.