1.Heat half of oil in a large frying pan on high. Cook beef in two batches, stirring, for 3 minutes, until browned. Transfer to a plate.
2.Heat remaining oil in same pan on medium. Cook onion and mushroom for 5 minutes, until onion softens. Add paprika and cook, stirring, for 1 minute, until fragrant. Add tomato, tomato paste and 1/4 cup of water, and mix well to combine. Bring to boil.
3.Return beef and any juices to pan. Reduce heat to low and simmer for 5 minutes, until beef is just cooked through. Season to taste.
4.Scatter goulash with parsley. Serve with sour cream sprinkled with extra paprika, if you like, and steamed rice.