Cook the mushrooms together with the lemon juice in a small, covered pot. Heat up slowly, cook for 2 minutes. Pour the liquid into a cup. Add some spices to the mushrooms, keep them warm.
Melt the margarine in a frying-pan. Add the onions, saute. Increase the heat, add the meat, add some water and roast gently. Turn the meat occasionally to make sure it gets roasted evenly. Remove the meat.
Add the white wine, let cook until the liquid thickens. Add the reserved liquid and the flour, cook until the sauce binds. Add the cream and increase the heat slightly. Add 1/2 t. paprika with some salt and pepper.
Sprinkle additional salt, pepper and ½ teaspoon paprika on the meat. Put meat into the sauce, increase the heat, but do not cook. Add the mushrooms. Sprinkle with parsley. Serve.