Combine flour, dry mustard, salt and pepper in a bowl, coat strips of meat evenly, set aside.
Melt 2 tablespoon of butter in 10 inch skillet, saute shallots and mushrooms until soft, remove from pan, set aside. In the same pan, melt the other 2 tablespoons of butter.over med.-high heat, brown and separate meat by stirring constantly for approx. 2-3 minutes. Do not over cook, juices should still be pink.
Add wine, water, Kitchen Bouquet and tomato paste to meat, simmer for 20 minutes, add mushroom shallot saute back to pan, stir and remove from heat, add sour cream and serve over rice or egg noodles.