2 tsp. dry mustard
2 tsp. salt
1 1/2 tsp. sugar
1 tbsp. water
4 lg. onions
1/2 c. oil
1 lb. med. sized mushrooms
2 cloves garlic
2 lb. beef filet
2 c. sour cream, at room temperature
1 1/2 tbsp. powdered flour (Wondra)
Freshly ground pepper
2 tbsp. snipped fresh dill or 1 tsp. dry

Combine mustard, salt, sugar and water in a small bowl, mix and set aside. Slice onions into thin semi-circles. Cut mushrooms into thick slices. Cut meat across the grain into thin strips 2 inches long and 1/4 inch wide. Set aside.

Heat large skillet with 2 tablespoons oil and saute the onions, mushrooms and minced garlic over high heat for 2 to 3 minutes, stirring all the while. Reduce heat to very low and cover. Cook until soft, about 15 minutes.

In separate skillet, heat 2 tablespoons oil until sizzling. Add about 1/3 of the meat and saute until partially cooked, about 1 minute. Place it with the vegetables. Saute the rest of the meat in the same manner until all is cooked.

Keeping a small fire under the skillet, now add the mustard paste and stir constantly. Sprinkle the flour over all and begin to add sour cream by spoonsful. Taste and correct seasonings. Serve on heated platter. Sprinkle dill over it. Serve with buttered noodles of rice pilaf.