Spray the bottom of a large saucepan, 5 times, with the low cal cooking spray. Turn on a high heat under the saucepan and wait until the oil bubbles, then turn down to a low heat. You could also use 1 tbsp. olive oil.

Add the diced onion and soften it, stirring continuously for about 4 – 5 minutes, then add the diced potato and the chopped mushrooms. Stir for a further 3 – 4 minutes.

Add the stock and simmer together for 20 minutes until the potatoes are soft. Remove from the heat.

When the soup has cooled, blitz it in a blender / food processor and return to the pan.

Add the milk, the corn flour, and then stir to thicken. Add more corn flour (mixed in cold water first) if a thicker consistency is required.

Season to taste and then serve garnished with the mushrooms and parsley.