The one challenge of making celery root soup is peeling the celery roots, which with their nobby-ness can be difficult. Use a sharp chef's knife to cut off the ends of the root. Then stand the root upright on a cutting board and use downward slices to cut the remaining peel off the the root. (The Kitchn has a great explanation here: http://www.thekitchn.com/how-to-peel-celery-root-74548). Then cut the roots in half, place the halves cut side down on the cutting board, and thinly slice them.
- 2 Tbsp butter
- 2 cups thinly sliced onions (sliced across the grain)
- 4 cloves garlic, sliced
- 2 medium fennel bulbs, thinly sliced
- 2 medium celery roots (about 1 1/2 pounds), peeled and thinly sliced (See TheKitchn's guide to peeling celery root)
- 1 medium russet potato, peeled and thinly sliced
- 2 bay leaves
- 7 cups chicken stock
- 2 1/2 teaspoons kosher salt (less or more to taste)
- 1/4 teaspoon black pepper
- 1/4 cup whipping cream
- Fennel fronds for garnish
1 Cook onions: Melt butter in a large (6-8 quart) thick-bottomed pot on medium high heat. Stir in the onions and cook until softened, about 4 to 5 minutes.
2 Add the garlic and the sliced fennel, lower the heat to medium and cook for 10 to 12 minutes or until softened.
3 Add the sliced celery root, sliced potato, 2 bay leaves, stock and salt. Increase heat to high, bring to a simmer, reduce heat to low, and maintain a simmer, partially covered for another 10 to 12 minutes, until all of the vegetables are soft enough to purée.
4 Purée the soup: Either working in batches with a standing blender (do not fill blender bowl more than a third full at a time), or with an immersion blender, purée the soup until smooth. (Note that an immersion blender will take several minutes longer than a standing blender to purée the soup to smoothness.)
5 Stir in cream and black pepper. Adjust salt to taste. Garnish with fennel fronds.