Place oil and onion into a 2-litre capacity dish. Microwave, uncovered, for 2 minutes on HIGH (100%) power. Add tomato paste. Cook a further 1 minute on HIGH.
Combine flour, paprika, salt and pepper. Add beef. Toss. Add to onion mixture. Stir in soup, stock and sauces. Microwave, covered, for 1 hour on DEFROST-MEDIUM LOW (30%) power, stirring every 10 minutes.
Add mushrooms and sour cream. Microwave 10 minutes on same power. Sprinkle with parsley. Serve with rice.