Sri Lanka Bistake Beef Steak Saute with Onion

Ingredients
BISTAKE
 * 450 gm Beef, Rump steak
 * 2 Onion
 * 75 ml Vinegar
 * 1 tsp Salt
 * 1 tsp Pepper, Black, coarse grind
 * 100 ml Oil
 * 1 Curry leaf sprigs
 * 2 cg Cinnamon stick
 * 1 tsp Mustard seed, ground
 * 100 ml Stock
 * 1 tsp Sugar
 * 1/2 tsp Chile powder

Directions

 * 1) Slice the beef into 50mm slices. Make onion rings with 1 1/2 onions and chop remainder. Mix together the vinegar, salt and pepper in a bowl and marinate beef for 1 hour.
 * 2) Heat the oil in a frying pan and when hot add the curry leaves, chopped onion and cinnamon stick. When fragrant add the beef and marinade. Cover pan and cook over a low heat until the beef is tender. Remove the beef and set aside.
 * 3) Add the onion rings to the pan and stir fry for a couple of minutes. Add the mustard, stock, sugar and chile powder and mix well. Put back the beef slices and cook for a further 2-3 minutes. Remove the cinnamon stick before serving.