Ingredients

  • 5 pounds asparagus, trimmed, cut into 2-inch pieces (14 to 15 cups)
  • 4 cups chopped leeks (white and pale green parts only; about 4 large)
  • 1/4 cup olive oil
  • 6 cups (or more) low-salt chicken broth
  • 2 tablespoons minced fresh Italian parsley
  • 4 teaspoons finely grated lemon peel
  • 1 tablespoon minced fresh tarragon
  • 1 small garlic clove, minced

Method

  • Preheat oven to 425°F. Combine asparagus, leeks, and oil in very large bowl; toss to blend. Divide between 2 large rimmed baking sheets. Sprinkle with salt and pepper. Roast vegetables until asparagus pieces are soft and leeks are golden, stirring occasionally, about 45 minutes; cool on sheets.
  • Spoon 1/3 of vegetables into blender; add 2 cups broth. Blend until smooth. Transfer to large pot. Repeat 2 more times, using half of remaining vegetables and 2 cups broth for each batch. Warm soup over medium heat, thinning with more broth by 1/2 cupfuls, if desired. Season with salt and pepper. DO AHEAD:
  • Mix parsley, lemon peel, tarragon, and garlic in small bowl for gremolata.
  • Ladle soup into bowls. Sprinkle with gremolata and serve.