Mix the corn flour, soy sauce, sesame oil and wine in a bowl.
Slice the beef across the grain then cut into 1cm thick strips. Add the beef to the marinade and stir to coat every strip well. Leave for at least half an hour if you can.
Heat up a wok until smoking. Add the vegetable oil and throw in the marinated beef.
Stir fry it for a minute, only until the strips colour slightly. Remove the beef back into the bowl and keep warm.
Add a little more oil to the wok if it looks dry. Add the chillies and then the vegetables.
Stir fry for 5 minutes until they start to colour a little.
Stir in the black bean and the sweet chilli sauce. Return the beef to the wok and stir everything around well.
When the vegetables look cooked, divide the stir-fry between plates and serve with plain noodles or rice.
