Here's one for the slow cooker. I haven't made it myself, but everything else I've pulled out of this book has been beautiful.

Prep time: 20 minutes. Cooking time: 2 hours. Serves 4

10g dried porcini mushrooms
1 leek, white part only, thinly sliced
100g pancetta or bacon, chopped
200g Swiss brown mushrooms, roughly chopped
300g large field mushrooms, roughly chopped
125ml Madeira (Malmsey) - if unavailable, use Sherry
1 litre chicken or vegetable stock
2 teaspoons chopped marjoram
90g light sour cream or creme fraiche
Marjoram leaves to garnish

Soak the porcini in 250ml boiling water for 20 minutes. Drain, reserving the soaking water.

Combine the porcini and the soaking water, leek, pancetta/bacon, swiss brown and field mushrooms, Madeira, stock and half of the chopped marjoram in the slow cooker. Cook on high for 2 hours.

Using a hand held stick blender, puree the soup. Alternatively transfer the soup mixture to a food processor and puree until smooth, then return the soup to the slow cooker.

Stir through the sour cream and cook for a further 5 minutes, then stir through the remaining chopped marjoram. Garnish with marjoram leaves and serve with crusty bread.