Cut the meat into strips, finely dice the onions and cucumber, clean and halve the mushrooms, fry the meat in portions in oil, season with salt and pepper. Remove the meat from the pan, briefly fry the mushrooms and onions in the frying fat, season, dust the flour over it, sweat, stir in a good 0.5 l of water and cream, bring to the boil, stir in the mustard, simmer for approx. 2 minutes, stir more often, meat and cucumber cubes Add, heat, season with salt, pepper, possibly a little sugar, finely chop parsley, sprinkle over the ragout, with spaetzle or rice and fresh salad.