45 ml (3 tbsp) vegetable oil
550 g (1 1/4 lb) boned top rib beef, cut into strips 2 inch x 1/2 inch
1 onion, skinned and sliced
30 ml (2 tbsp) plain flour
300 ml (1/2 pint) beef stock
salt and freshly ground pepper
1 small green pepper, halved, seeded and sliced
175 g (6 oz) button mushrooms, wiped and sliced
142 ml (5 fl oz) carton soured cream, stirred
chopped parsley, to garnish