In a large pot heat the oil, and sauté the chopped onion and sliced leek for about 3 mins.
Next, add washed and sliced mushrooms and fry for another 10 minutes stirring now and then.
Add the carrot, parsnip and potato. Mix well and cook for 3-4 mins. Season with salt and pepper.
Pour in the hot vegetable stock and bring to the boil. Simmer, covered for about 15 mins. until the vegetables are soft.
Mix with a hand blender until smooth, add cream at the end and serve.