Asparagus, Spinach and Leek Soup

This silky green soup is built on asparagus, with leeks and fennel for sweetness, zucchini for body and a big handful of spinach and herbs. It's a good home for a spring market haul.

Serves 4 · 40 minutes

Ingredients

• 2½ tablespoons extra-virgin olive oil, divided
• 3 leeks, white and light green parts only, thinly sliced
• ¼ teaspoon red-pepper flakes
• 2 teaspoons kosher salt, divided, plus more to taste
• ½ teaspoon freshly ground black pepper, divided, plus more to taste
• 4 garlic cloves, minced
• 1 large fennel bulb with fronds, trimmed and diced, fronds saved
• 2 medium zucchini (about 12 ounces), trimmed and cut into 1-inch pieces
• 1 bunch asparagus (about 1 pound), trimmed and cut into 1-inch pieces, tips kept separate
• 4 cups vegetable stock
• 1 cup chopped cilantro, mint or parsley leaves and tender stems
• 1 cup chopped dill fronds and tender stems
• 10 ounces baby spinach
• 1 to 2 tablespoons fresh lemon juice

Instructions

1. Warm 2 tablespoons of the oil in a soup pot over medium-high heat for about 30 seconds. Add the leeks, red-pepper flakes, ½ teaspoon salt and ¼ teaspoon pepper and cook until the leeks are browned at the edges, about 5 minutes. Stir in the garlic and cook 1 minute more.
2. Add the fennel, zucchini, 1 teaspoon salt, the remaining ¼ teaspoon pepper and the asparagus stem pieces, saving the tips. Cook, stirring now and then, until the vegetables turn bright green, about 5 minutes.
3. Pour in 3½ cups of the stock and bring to a simmer. Lower the heat and cook gently until everything is very soft, 10 to 15 minutes.
4. Meanwhile, heat the remaining ½ tablespoon oil in a small skillet over medium-high heat. Add the asparagus tips and a pinch of salt and cook until just tender, 2 to 3 minutes. Set aside for garnish.
5. Stir the herbs and about 1 cup of the fennel fronds into the soup, keeping the rest of the fronds for the top. Add the spinach a handful at a time, letting each batch wilt, then stir in the last ½ teaspoon salt.
6. Purée until smooth with an immersion blender, or in batches in a blender or food processor. Add the remaining ½ cup stock if you want it thinner.
7. Stir in the lemon juice, then taste and add more salt and pepper as needed. Ladle into bowls and top with the asparagus tips and fennel fronds.

Tips

• The soup is greenest right after blending and darkens as it sits, though the flavor holds.
• It thickens in the fridge, so loosen it with a splash of stock or water when you reheat it.

Adapted from Melissa Clark, NYT Cooking.