Heat the olive oil in the soup pot, add onion and leeks and celery, allow to caramelize over medium heat for 10 minutes. Add the salt, garlic and thyme and saute 3 more minutes.
Add the wine, raise the heat and reduce for 3 minutes. Add the mushrooms and cook them with the onion mixture over medium-low heat for 6 minutes, stirring part way through cooking. Pour in the soaked mushrooms, stock and add tofu. Taste and add more sea salt, if necessary. Lower heat and simmer for 20 minutes.
Remove thyme branches. Let the soup cool slightly and then puree in the blender to make a smooth creamy soup.
Garnish with fresh thyme or parsley, Sauteed mushrooms, and a spoonful of tofu sour cream if you are feeling decadent.
Cover the dried mushrooms with 1 cup hot water and set aside. Heat the olive oil in the soup pot and add the onions to caramelize. When they have turned a deep brown add the remaining vegetables, herbs, garlic, sea salt and saute an additional 3 minutes (add a little liquid if necessary). Add the dried porcini and their soaking liquid plus 9 cups cold water, and bring to a boil. Simmer for 45 minutes uncovered. Strain the stock through a fine mesh colander.
Use as is or return it to the stove to reduce and intensify the flavor. A general rule of thumb: it takes about 15 minutes at a slow boil to reduce the volume of liquid by one cup. Yield: 6 to 8 cups