Ingredients

• 6 tablespoons olive oil, divided, plus more for drizzling
• 2 medium onions, thinly sliced
• 3 pounds asparagus cut into 1/2" pieces
• Kosher salt and freshly ground black pepper
• 4 cups low-salt chicken broth
• 8 ounces fresh spinach
• 6 thin asparagus spears, tips removed, stalks halved crosswise, thinly sliced lengthwise

Instructions

1. Heat 4 tablespoons oil in a large pot over medium-low heat. Add onions and cook, stirring occasionally, until translucent, 8-10 minutes. Add 1/2" asparagus pieces and season with salt and pepper. Cook until asparagus is bright green and tender, 4-5 minutes. Add broth, increase heat to high, and bring to a boil. Reduce heat to medium and simmer until asparagus is tender, 8-10 minutes. Add spinach and cook, stirring occasionally, until wilted, about 2 minutes. Let mixture cool slightly.
2. Set a fine-mesh sieve over a large bowl; set aside. Working in batches, purée soup in a blender until very smooth. Strain through prepared sieve. Stir remaining 2 tablespoons oil into soup; season to taste with salt and pepper. Cover and chill until cold, at least 3 hours. DO AHEAD: Can be made 1 day ahead. Keep chilled.
3. Divide asparagus tips and thinly sliced stalks among bowls; pour chilled soup over. Drizzle each with a few drops of oil.