Heat the oil in a non-stick pan over medium-high heat. (Use a pan just big enough to hold the meat in one layer. The sauce will cook away in a larger pan.) Beef brown on all sides, about 3 to 4 minutes. Put on a plate.
Add the onion and mushrooms to the pan. Fry for 2 minutes. Add the stock, water, tomato paste, mustard and pasta. Mix thoroughly. Bring to a boil, lower the heat to medium, cover with a lid and simmer for 10 minutes. Reduce the heat to low and return the beef to the pan. Let simmer for 2-3 minutes. Taste. You may need to add a little more mustard. There should be a delicate blend of flavors.
Stir in sour cream and add black pepper to taste. Mix thoroughly. Divide between two plates and sprinkle with parsley.
Nutritional information per serving: 505 calories, 113 calories from fat, 12.5 g fat, 3.4 g saturated fat, 5.2 g monounsaturated fat, 118 mg cholesterol, 43.2 g protein, 59.6 g carbohydrates, 5.8 g fiber , 9.0 g sugar, 593 mg sodium, 1,404 mg potassium, 650 mg phosphorus
Exchanges: 3 starch, 2 vegetables, 4-1 / 2 lean protein
Recipe from: “Delicious One-Pot Dishes” by Linda Gassenheimer, published by the American Diabetes Association; Reprinted with permission.