Beef with Leeks (with mustard and red chilli oil)

450g beef, sliced finely
1 tsp salt
1 ½ tsp cornflour
1 egg white
3 slices root ginger, shredded
225g (3) leeks, sliced finely slantwise
4 tbsp vegetable oil
1 oz lard
1 tbsp light soy sauce
2 tbsp good stock
1 tbsp english mustard
2 tsp red chilli oil

Method
1. Rub the sliced beef with salt and toss with corn flour and egg.
2. Heat oil, when hot fry ½ the ginger for 30 secs, Add leeks and stir fry for 1 ½ mins, remove.
3. Add the lard, when hot stir fry the beef for 1 ½ mins. Add soy and remaining ginger.
4. Add the leeks back into the pan and stock. Toss for 30 secs.
5. Transfer to serving dish. Drizzle the mustard and red chilli oil.