Recipe by Michael Aviad found on A Sweet Life
2 lb Jerusalem artichoke, peeled and sliced
3 medium Leeks, white and light green parts only, washed well and sliced
2 Garlic cloves, minced
1 Celery stalk, chopped
1/4 cup Thyme leaves
1/2 cup Olive Oil
1 cup Cream
Salt & Pepper to taste
Heat the oil in a large pot over a high flame. Add the onion, celery and leek and cook for 7 minutes while stirring. Add the Jerusalem artichoke, thyme and garlic and cook for another 7 minutes, and stir.
Add 8 cups of water, bring to a boil, then lower flame and let it cook for 30 minutes. Make sure the Jerusalem artichoke is soft and remove from heat. Puree the contents of the pot using a hard blender until smooth, add salt and pepper, and return to the stove. Bring the soup to a boil, lower the flame and allow it to cook for 15 minutes. Stir in the cream, salt and pepper and continue cooking for several minutes without letting the soup boil. Serve hot.