In a small bowl, mix together the soy, mirin, and cornflour paste.
Heat the oil in a wok or large frying pan. Season the beef and sear in batches, then remove to a plate and cover with foil to keep warm.
Fry the chilli, then add the spring onions and beansprouts, and stir-fry for 2 mins.
Return the beef to the wok and add the spinach and garlic oil along with the sauce.
Keep stir-frying for another 2-3 mins until the spinach has wilted.
Serve sprinkled with the sesame seeds and some rice, if you like.
Recipe from Good Food magazine
1 tbsp soy sauce
1 tbsp mirin
2 tsp cornflour, mixed to a paste with 2 tbsp water
1 tbsp vegetable oil
300g beef frying steak, thinly sliced
1 tbsp garlic infused oil
1 red chilli, finely chopped
3 spring onions, sliced into small pieces - green only
300g pack beansprouts
100g bag baby spinach
handful sesame seeds, toasted
cooked rice, to serve (optional)