Cut the meat into steaks with a thickness of 1-1,5 cm Not to discourage. For the marinade : mix salt, pepper, olive oil and balsamic vinegar ( not to be replaced by another form). If not garlic salt, then add the usual pinch of garlic powder.

Put the meat in the marinade, thoroughly coat each piece and leave for 2 hours. Onion cut into semi rings and fry in vegetable oil for 5-7 minutes.

To the onions add the Apple sliced. Remove seeds, peel leave. To reduce the fire and stew the apples together with the onions until the apples are soft. Then add sour cream and pour 50 ml of water. Saute all together for 4-5 minutes.

Apple-onion stuffing to shift in the bowl of a blender, add the mustard, 10 tablespoons of water or broth and a pinch of salt. Blend into a homogeneous mass. Water can add more if you want a more liquid sauce. The pan heat, put butter and a bit olive. On high heat fry the steaks on both sides until Browning. Then the fire abated, pour 50 ml of water or broth and when the cover is closed to braise meat until tender. Focus on how rare you like the meat. I like well-cooked meat. The meat is ready to serve fresh vegetables and herbs, abundantly watering sauce slices of meat.