One hour before cooking, place the roast in the freezer. It will firm it up and make it easier to slice. {I defrosted mine in the fridge and just made sure the center was still a little frozen.} Cut the meat into 1/2 inch strips.

Season the meat and flour liberally with salt and pepper. Allow the meat to rest a minutes so that the salt can pull a little moisture to the surface, then dredge in season flour.

Heat a large pot to medium-high heat. Add 1 tablespoon each butter and oil. When the butter begins to foam, add just enough of the meat to barely cover the bottom of the pot. Do not crowd the pan. Turn strips until they’re brown on all sides, then remove to a rack resting over a baking sheet (with a lip). Continue browning the meat in batches, adding more butter and oil as needed.

When all the meat has been browned, pour off any grease from the pan, add the remaining tablespoon butter, then add the shallot, garlic, and mushrooms to the skillet and saute until brown.

Using a shaker or sifter, sprinkle a couple teaspoons of season flour over the top of the vegetables and toss to coat. Deglaze the pot with the wine, using a spatula to scrape up any stubborn bits. Stir in the mustard and return the meat and any drippings to the skillet. Add enough beef broth to barely cover the meat.

Drop the temperature to a simmer, and cover. Cook for 45 minutes, stirring occasionally. Stir in sour cream an serve over wide egg noodles or rice.