Blanch the potatoes in boiling water for 3-4 minutes then drain thoroughly. Meanwhile heat the oil in a wok or large frying pan and stir-fry the beef for 2-3 minutes or until browned.
Add the mushrooms, pepper, onion, paprika and potato slices and cook for a further minute.
Stir in the tomato sauce and stock, leave to gently simmer for 10 minutes – longer to reduce and thicken the sauce if preferred.
Serve in bowls topped with a spoonful of yoghurt and fresh herbs or a dusting of paprika.
For a slow cook Goulash, use Beef shoulder or featherblade, cubed and cooked with the above ingredients in a lidded casserole for 2½ hours at 140°C. Add a little more stock if required halfway through cooking.