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. 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.