From start to finish, making the soup took about an hour. The rich mushroom flavor was exquisite and we're ready for lunch tomorrow when the soup will be even better!
Soak the dried mushrooms in 1 cup of warm water for 20-30 minutes, until plump and the water is brown and smells like an earthy mushroom broth.
Remove the mushrooms. Strain the soaking liquid through a coffee filter to remove any grit and reserve. Add the mushrooms back into the bowl with the liquid and set aside until needed.
In a large soup pot over medium heat, add the olive oil. Bundle the herbs together using kitchen twine and, when the oil is hot, add the herb bundle and sizzle for a few minutes on each side to infuse the oil. Add the onion, garlic, salt and white pepper and cook for 8 minutes or so, until the onion is soft and translucent but not brown.
While the onions are cooking, slice the mushrooms. Turn the flame to high and add the sliced mushrooms. Cook for 10 minutes. The mushrooms will release their liquid (which will evaporate with the heat) and deflate significantly. Stir occasionally. Once the mushrooms have wilted, add the stock, water, reconstituted mushrooms and the soaking liquid. Simmer for 30 minutes.
Remove the herbs and add the cream and butter. Stir well so the butter melts into the soup. Using an immersion blender, puree the soup. Alternatively, you could puree the soup in the blender until smooth.
Keep the soup on very low heat until ready to serve. Ladle generously into bowls, sprinkle with a bit of Maldon salt, top with a few grinds of fresh black pepper, a bit of chopped parsley for color and dig in. Refrigerate any leftover as it will be even better the next day.