Spicy Lemon-Ginger Chicken Soup

Ingredients

• One 4-pound whole chicken, innards removed
• 1 large yellow onion, peeled and chopped into large pieces
• 2 medium carrots, chopped into large pieces
• 2 celery stalks, chopped into large pieces
• 1 large head garlic, cut crosswise
• ½ to 1 jalapeño, cut lengthwise, plus more for garnish
• Two 3-inch pieces ginger, peeled and chopped
• 1 large bunch fresh parsley, plus more for garnish
• 1 tablespoon coriander seeds
• 1 tablespoon kosher salt
• 2 teaspoons freshly ground black pepper
• 6 ounces fresh spinach or other tender greens
• 2 lemons, thinly sliced