Prep the ingredients. Thinly slice the onion. Clean the mushrooms and slice them. Take the creme fraiche and heavy cream out of the refrigerator and let them come up to room temperature.

Using a meat mallet, tenderize the meat. If you don’t have a meat tenderizer or mallet, you can just use your fist.

Cut the beef into 1/2 inch(1 cm)-wide slices, and add a dash of salt and pepper.

Preheat a pan over high heat and add 1 tbsp of sunflower oil. Add half of the meat slices and cook each side for about 1 minute until browned on the outside but still pink on the inside. Remove the cooked beef strips to a plate.

Repeat step 4 with the remaining half of the beef strips. Remote the beef strips, and set aside on a plate.

Turn the heat down to low, and add the butter to the pan.

Add the thinly-sliced onion to the pan with the melted butter, and cook for about 1 minute.

Add the sliced mushrooms to the pan and cook until golden brown.

Add the cognac to the pan. Simmer until the liquid thickens.

Add the fresh cream, nutmeg, mustard, and creme fraiche, and cook for 2 more minutes with the lid on.

Add the meat (and the accumulated meat juices) back to the pan, and simmer this mixture for 2-3 more minutes on a low flame (or until the beef is cooked to your taste)

Let it cool a touch, season it to taste with salt and pepper, and serve it over mashed potatoes, rice, pasta, or noodles.

Приятного аппетита! Enjoy your Meal!