What should be Russian about the dish is a mystery to me, but it is super easy to make and tastes great.
Peel and dice the onions, clean and wash the leek and cut into rings. Heat the oil and butter in a saucepan, fry the onion cubes in it. Increase the heat and fry the minced meat in it until crumbly. Now lower the heat again, add the leeks, tomato paste, broth, mustard and spices. Braise for about 15 minutes, stirring frequently. Stir in the sour cream just before serving and season everything again vigorously.
Preferably pasta and mixed or green salad as a side dish.