Prep. time: 15 minutes
Cooking time: About 1 1/4 hours

Jerusalem artichokes - those knotty, crunchy little balls that look like malformed potatoes or pieces of ginger root - are the unexpected base for this soup. These tubers have the refreshing flavor of water chestnuts, but are in fact the root of a plant of the sunflower family. Jerusalem artichoke season begins in late summer and lasts until mid-February, but they are often hard to find. If you can't get them, you could also make this soup with artichoke hearts, which are available starting in the spring.

To add extra crunch and flavor, I serve this soup with sautéed croutons with garlic and sage.

One more thing about the Jerusalem artichokes: you don't need to peel them for this recipe. Just scrub them well. Their skins add character to the soup.  

The soup can be made in advance, cooled, covered well and refrigerated overnight. Reheat gently before serving. 

1. Melt the butter in a large saucepan or Dutch oven; add the bacon and cook, stirring occasionally, until its fat has rendered, about 3-5 minutes; remove the bacon;
2. add the onion, fennel, leek, celery and garlic to the pot; season with salt and pepper; add the bouquet garni and cook, stirring occasionally, for 5 minutes; add the Jerusalem artichokes and cook 15-20 minutes longer, stirring occasionally; 
3. add the stock, potatoes, salt and pepper; bring to a boil, then reduce to a simmer; cook uncovered for 30-35 minutes, skimming the surface often; discard the bouquet garni; 
4. purée the soup in a blender until smooth and creamy; strain into a clean saucepan; 
5. add the cream; bring to a boil and correct the seasoning if necessary; 
6. reduce the heat and keep the soup hot while you make the croutons. 

Preparing the croutons

1. Heat the oil in a small skillet over medium heat; add the bread cubes, sage, garlic, salt and pepper; 
2. sauté the croutons until they are crispy and golden;
3. discard the garlic and drain the croutons on paper towel; keep the crispy sage leaves for garnish.  

Serving