1. Heat the olive oil and butter in a large pot over a medium heat. Add the onion and cook for 6-7 minutes until soft and translucent. Add the garlic, bay leaf, thyme and peppercorns, stir together and cook for one minute.
2. Add the potatoes, mushrooms and stock. Stir everything together and bring to the boil. Reduce the heat to low, place the lid on the pot and simmer for 20 minutes.
3. Remove the bay leaf and blend the rest until smooth using a stick blender or in the bowl of a food processor.
4. If using a food processor, return the soup to the pan. Place it back over the heat and bring to a boil. Add the milk and adjust the seasoning.
5. Ladle the soup into serving bowls and add a swirl of crème fraîche and chopped parsley.

Per Serving 166kcals, 9.7g fat (5.2g saturated), 16.5g carbs, 4.7g sugars, 5.3g protein, 3g fibre, 0.306g sodium