Celery Root and Cèpe Soup

From Food&Drink, Autumn 2006, page 198.

Haven't tried this yet but it looks fabulous!

"This is a sophisticated rich soup, and the croutons, while not essential, provide and interesting contrast in texture"

1/2 oz (15 g) dried cèpes (or porcini)
2 medium onions
1 celery root, about 5 inches in diameter
2T unsalted butter
2 T olive oil
2 t kosher salt
freshly ground pepper
1 c light cream
fried bread croutons, optional

1. Place the dried mushrooms in a bowl and pour over 3 cups boiling water. Leave the mushrooms to soak for 20 minutes.
2. Peel and dice onions and celery root. In a large frying pan with a lid, heat the butter and oil over medium-low heat. Add the onions, celery root and salt. Stir to coat the vegetables, cover and cook gently for 15 minutes.
3. Remove the dried mushrooms from the soaking liquid, chop them coarsely and add to the vegetables. Carefully strain the soaking liquid through a fine sieve and pour into the pan (not sure why you're supposed to strain...a mushroom bit is a mushroom bit, as far as I'm concerned). Cover and cook until the vegetables are very soft, about 15 mins. Season with pepper and more salt if necessary and let cool slightly.
4. Puree the vegetable mixture in batches in a blender, then pour into a saucepan. Add cream, then heat the soup gently. If it seems too thick, add more water.
5. Serve topped with croutons, if desired.

The recipe says this soup serves 6-8.....but with only 3 cups of liquid, I would bank on it serving four people. I also fail to understand why recipes never mention the magic of the immersion blender. WHY in god's name would you dirty a blender, as well as another bowl (and mess with pouring hot chunky soup) when you could just use a nice little immersion blender to accomplish nearly the same thing. It won't be *quite* as smooth, but it will still rock. And you will have fewer dishes. :) How can that be a bad thing????