Ingredients

• 4 lb. raw chicken bones
• 3 spring onions or 4 scallions, chopped
• 4 garlic cloves, crushed
• 3 oz. thinly sliced prosciutto, chopped
• 3/4 cup dried porcini mushrooms, rinsed
• 1/3 cup extra-virgin olive oil, plus more for drizzling
• 4 (1/2"-thick) slices country-style bread
• Kosher salt
• 10 oz. asparagus (about 1 bunch), trimmed, thinly sliced on a diagonal into 1"–1 1/2" pieces
• 4 oz. button mushrooms, stems trimmed, very thinly sliced
• 2 cups pea shoots (tendrils)
• 1 Tbsp. fresh lemon juice
• Finely grated Parmesan (for serving)
• Freshly ground black pepper

Instructions

1. Bring chicken bones and 12 cups cold water to a gentle simmer (you don’t want it to boil) in a large pot. Reduce heat to medium-low and cook at a bare simmer, skimming foam occasionally, until stock is reduced by one-third, 2 1/2–3 hours.
2. Add spring onions, garlic, prosciutto, and mushrooms to pot and cook another 20 minutes. Strain stock through a fine-mesh sieve into a medium bowl; discard solids (you should have about 9 cups). Pour 3 cups brodo into an airtight container; reserve for another use.
3. Do Ahead: Brodo can be made 3 days ahead. Cover and chill.
4. Heat 1/3 cup oil in a medium skillet over medium. As soon as the oil begins to look glossy, add bread slices and cook until golden brown, about 3 minutes per side. Transfer to a plate and season lightly with salt.
5. Pour brodo into a large saucepan and bring to a simmer over medium heat. Taste and season with salt. Add asparagus and cook until tender and bright green, about 3 minutes. Remove from heat; add mushrooms.
6. Toss pea shoots and lemon juice in a medium bowl; season with salt.
7. Divide soup among bowls and place a piece of fried bread into each one. Top with dressed pea shoots and Parmesan. Drizzle with lots of oil and season with pepper.