Lightly brown half of the onions in the butter. Add the chopped garlic clove and brown briefly. Now add the mushrooms and deglaze with a little water, put the lid on the pan and simmer for about 3 minutes at medium temperature. Then reduce the temperature and stir in the sour cream and whipped cream. There is also a tablespoon of tomato paste and mustard. Season with salt and pepper.
In a second pan, the beef fillet cut into strips is briefly fried in oil. A few onions and salt and pepper are added. The meat is ideal when it is brown on the outside and slightly bloody on the inside. The sour pickles are added to the sauce and the whole thing is left to steep for a moment. Put the seared meat in the sauce and let it steep for a short time, add a little lemon juice and finally season with salt and pepper.
We like the stroganoff filetragout best with spaetzle or ribbon noodles.