Heat the oil in a large frying pan, and cook the onion, garlic and mushrooms over a medium heat for 5-10 minutes, until slightly softened. Add the vegetable stock and smoked paprika, and season well with black pepper (and a little salt if you used low sodium stock). Cook for a further 5 minutes.Just before serving, stir in the sour cream and half of the parsley, and once heated through, serve topped with the remaining parsley. I served mine alongside a wild rice mixture.