Ingredients
Method
1.In a small bowl, cover dried porcini mushrooms with boiling water and set aside 15 minutes.
2.Meanwhile, in a large saucepan, heat butter and oil over medium high heat. Add onion and Swiss brown mushrooms and cook for 10 minutes, stirring occasionally.
3.Drain porcini mushrooms, reserving soaking liquid. Add porcini, thyme and garlic to the pan. Continue to cook for 5 minutes, stirring regularly.
4.Add white wine to the pan and allow most of it to evaporate before adding stock and reserved mushroom liquid. Increase heat to high and allow to simmer for 10 minutes. Remove thyme sprigs, discard.
5.Remove from the heat, ladle into a blender and process until smooth. Return to saucepan and stir through creme fraiche. Season to taste
6.Ladle into bowls top with a teaspoon of cream fraiche, a sprinkling of chives and a drizzle of truffle oil.