1Combine flour and paprika in a large bowl. Season. Toss beef in flour mixture to lightly coat.
2Heat 2 tsp oil in a large frying pan over high heat. Brown the beef in 3 batches using 2 tsp oil per batch. Transfer to a plate. Set aside.
3Reduce heat to medium-high. Add remaining 1 tbs oil, onion and garlic to pan. Cook, stirring, for 3-4 minutes or until onion softens. Add mushrooms. Cook, gently stirring, for 4-5 minutes until mushrooms are just soft.
4Return beef to pan. Stir in stock, Worcestershire sauce, tomato paste and sour cream. Season. Bring just to the boil, stirring often, until well combined and hot. Sprinkle with parsley. Serve with fettucine or mashed potatoes.