Directions

  1. Heat oil in a large sauce-pot over medium-high heat; add onions and cook 5 minutes or until tender, stirring occasionally. Add celery, carrots and cauliflower; cook 10 minutes or until starting to brown, stirring occasionally. Add sweet potato, celery root and stock; heat to a simmer. Reduce heat to medium-low; cover and cook 45 minutes or until vegetables are very tender.
  2. Toast hazelnuts in a small skillet over medium-low heat 3 minutes or until lightly browned and fragrant; add mustard seeds, if using, and cook 2 minutes or until mustard seeds start to pop, stirring frequently.
  3. Purée soup in batches in a blender on high 1 minute or until smooth; transfer back to sauce-pot and stir in salt. Makes about 10 cups.
  4. Serve soup topped with hazelnut mixture garnished with oil and thyme, if desired.

Tips & Tricks

To freeze soup, cool puréed soup in sauce-pot in sink filled with ice water. Divide soup into freezer-safe containers and freeze up to 3 months. Thaw soup overnight in the refrigerator, cover and reheat on the stovetop (or in a microwave-safe dish in microwave oven on high) until internal temperature reaches 165°F. Prepare toasted hazelnut mixture before serving.