For this recipe I cheat by using a can of mushroom soup. It's just make the cooking a whole lot easier.Start by cutting the roast beef into bite sized pieces. Fry the onion in oil and butter. After they are translucent, put in the roast beef, mushroom soup, water (enough to dilute the soup so it makes a sauce), sour cream, a bit of paprika, salt and pepper.
Cook over low heat, but since you already have cooked meat, it will not take that long.
Serve with pasta.
