A little background on Moosewood if you don't know. The book I have is the 15th anniversary, New Revised Edition by Mollie Katzen; which means the recipes are a little lighter and use less dairy and eggs. The cookbooks are vegetarian and she also has a restaurant named Moosewood in Ithaca New York.
Now for the bisque... (side note, this could easily be made vegan if you wanted)
2 medium potatoes, I used russet
1 1/2 cups water
1 1/2 Tbsp butter or margarine
2 cups chopped onion
1 small stalk celery, chopped
1 1/2 lbs mushrooms, I used button
1 1/2 to 2 tsp salt
1 to 2 small cloves or garlic, minced
1/4 tsp thyme
3 Tbsp dry sherry
2 tsp soy sauce
Fresh black pepper to taste
1 cup milk, or soy milk
Peel potaoes, chop into small pieces, and place in a small saucepan with water. Cover, bring to a boil, and simmer until potatoes are tender.
Meanwhile, melt butter in a deep skillet or Dutch oven. Add onion and celery, and saute over medium heat for about 5 minutes. Stir in mushrooms and salt, cover, and cook about 10 minutes, stirring occasionally. Somewhere in there, add garlic and thyme. (Adding garlic later keeps its flavor stronger.) Remove from heat; stir in sherry, soy sauce and pepper.
Use a blender or food processor to puree both the potatoes in their cooking water and the mushroom saute in its own liquid. (When you run out of the liquid use the milk.) Combine yhe purees in a kettle or Dutch oven.
Stir, and heat gently; taste to adjust seasonings. Serve very hot, with optional but highly recommended toppings.