Leek and Fennel Soup Recipe

This Leek and Fennel Soup recipe blends tender leeks, onions, fennel, butter, and vegetable stock into a silky, aromatic soup topped with crisp homemade croutons. Featured on Cook the Books: Celebrity Edition Season 3, this elegant recipe prepared by host Shahir Massoud makes a comforting appetizer or light vegetarian meal.

The Inspiration

Leeks and fennel are a natural pairing for a smooth vegetable soup. Leeks contribute a gentle onion flavour, while fennel brings a subtle sweetness and light anise-like aroma. Cooking the vegetables until completely tender softens their sharper qualities and allows them to blend into a balanced, delicate soup.

This Leek and Fennel Soup comes directly from Martha: The Cookbook and is featured on Cook the Books: Celebrity Edition Season 3 with host Shahir Massoud. The recipe reflects the cookbook’s polished approach to familiar ingredients, transforming simple vegetables and stock into a refined dish with an elegant presentation.

Shahir Massoud demonstrates how the croutons can be baked while the soup simmers, allowing the complete dish to come together in approximately one hour. The finished soup is suitable for a casual lunch, an elegant dinner party, or the opening course of a holiday meal.

Ingredients

For the Soup

8 leeks, white and light green parts only
2 tbsp unsalted butter
2 yellow onions, finely chopped
6 fennel bulbs, finely chopped
Kosher salt and freshly ground pepper
6 cups vegetable stock

For the Croutons

½ (1 lb) loaf day-old bread (such as brioche), crusts removed and cut into ¼-inch cubes
2 tbsp extra-virgin olive oil
1 tbsp unsalted butter, melted
Kosher salt and freshly ground pepper
Chervil sprigs, for serving

Method

Clean the leeks thoroughly: place in a large bowl of cold water; stir and let stand for 5 minutes. Lift out leeks, discard water, and rinse out bowl; repeat as necessary. Transfer the leeks to paper towels to drain. Finely chop.
Meanwhile, melt the butter in a large pot over medium-low heat. Sauté the onions, stirring occasionally, until softened and translucent, about 10 minutes.
Add the chopped leeks and fennel and cook over medium-high heat until the vegetables are tender, about 15 minutes. Season with 2 tsps salt and a pinch of pepper. Add the vegetable stock and bring to a boil; reduce the heat and simmer for 20 minutes.
Meanwhile, make the croutons: Preheat the oven to 350F. On a rimmed baking sheet lined with parchment, toss the bread cubes with olive oil, melted butter, 1 tsp salt, and ½ tsp pepper. Bake in a single layer until the croutons are toasted and crisp, 12 to 15 minutes, tossing halfway through.
Carefully transfer the vegetable soup to a blender, working in batches if needed, and puree until smooth. Adjust the soup’s consistency. Season with salt and pepper to taste. Top with croutons and chervil before serving.

Serving Suggestions

Serve Leek and Fennel Soup hot as an elegant appetizer before roasted vegetables, pasta, fish, chicken, or a holiday main course. Its smooth texture and delicate flavour prepare the palate without making the complete meal feel overly heavy.

For a light vegetarian lunch, pair a larger bowl with a green salad, roasted vegetable salad, or warm crusty bread. The buttery homemade croutons add enough texture to make the soup feel satisfying while preserving its refined character.

The soup is particularly suitable for autumn and winter meals, but the fresh flavour of leeks, fennel, and chervil also works well during spring. Serve it in smaller cups or bowls as the opening course for a dinner party, Easter gathering, Thanksgiving meal, or Christmas celebration.

Final Thoughts

This Leek and Fennel Soup recipe transforms simple vegetables into a silky and memorable dish. Slowly cooked onions provide a savoury foundation, while leeks and fennel create gentle sweetness and a delicate aromatic flavour.

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