1 tablespoon sunflower oil1 tablespoon sunflower oil
300 g sirloin steak - cut into thin slices of 0,5 centimeters, against the grain and long ones i half300 g sirloin steak - cut into thin slices of 0,5 centimeters, against the grain and long ones i half
40 g butter
1 onion - peel, cut in half and cut into thin slices
500 g white mushrooms - clean with a dry brush, trim the stem if tough or dirty, then roughly cut into slices
2 tablespoons plain flour T55
250 ml beef broth250 ml beef broth
200 ml crème épaisse
1 tablespoon Dijon mustard
salt - to your taste
black pepper - freshly ground from a pepper mill, to your taste
