*miso paste adds a delicious savoury richness to the soup
Heat the oil and half the butter in a large pan over a low heat. Add the onion, garlic and cook for 7 minutes.Add the leek and sweet potato and cook for 5 minutes. Stir in the sherry and miso paste.Reserve 50g of each mushroom and add the balnce of the mushrooms to the pot. Cook for 3 minutes.Add the stock and thyme leaves. Bring to a boil then simmer for 10 – 15 minutes. Remove the pan from the heat and cool.Blend in a blender, retune the soup to the pan and reheat, adding the cream seasoning to taste.Meanwhile, melt the remaining 25g butter in a frying pan over a medium heat. Fry the reserved mushrooms until golden and browned.Ladle the soup into bowls, drizzle with extra cream and garnish with pan-fried mushrooms and fresh thyme.